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HISTORICAL CHRONOLOGY
| Editor's note: This is a historical chronology principally devoted to marking milestones in human scientific achievement and is intended to provide a valuable reference that will enable readers to relate dates and events mentioned in the text to the larger scope of related scientific achievement. Although mention is made of epidemics and pandemics, it is beyond the scope of this chronology to provide a comprehensive listing of such events.
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ca. 10000 B. C.
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Neolithic Revolution: transition from a hunting-and-gathering mode of food production to farming and animal husbandry, that is, the domestication of plants and animals.
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ca. 3500 B.C.
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Sumerians describe methods of managing the date harvest.
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ca. 700 B.C.
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The use of anatomical models is established in India.
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ca. 600 B.C.
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Thales, the founder of the Ionian school of Greek philosophy, identifies water as the fundamental element of nature. Other Ionian philosophers construct different theories about the nature of the Universe and living beings.
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ca. 500 B.C.
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Alcmaeon, Pythagorean philosopher and naturalist, pursues anatomical research and concludes that humans are fundamentally different from animals. He also differentiates arteries from veins. His work establishes the foundations of comparative anatomy.
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ca. 450 B.C.
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Empedocles, Greek philosopher, asserts that the Universe and all living things are composed of four fundamental elements: earth, air, fire, and water.
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ca. 430 B.C.
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Plague of Athens caused by unknown infectious agent. One third of the population (increased by those fleeing the Spartan army) die.
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ca. 400 B.C.
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Hippocrates, Greek physician, establishes a school of medicine on the Aegean island of Cos. According to Hippocratic medical tradition, the four humors that make up the human body correspond to the four elements that make up the Universe. Hippocrates suggests using the developing chick egg as a model for embryology, and notes that offspring inherit traits from both parents.
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ca. 400 B.C.
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The Greek philosopher Democritus argues that atoms are the building blocks of the Universe and all living things. Democritus was an early advocate of the preformation theory of generation (embryology).
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ca. 350 B.C.
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The Greek philosopher Aristotle attempts to classify animals and describes various theories of generation, including sexual, asexual, and spontaneous generation. Aristotle argues that the male parent contributes ``form'' to the offspring and the female parent contributes ``matter.'' He discusses preformation and epigenesis as possible theories of embryological development, but argues that development occurs by epigenesis.
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ca. 50 B.C.
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Lucretius proposes a materialistic, atomistic theory of nature in his poem On the Nature of Things. He favors the preformation theory of embryological development.
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ca. A.D. 70
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Roman author and naturalist Pliny the Elder (A.D. 23–79) writes his influential Natural History, a vast compilation combining observations of nature, scientific facts, and mythology. Naturalists will use his work as a reference book for centuries.
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ca. 160
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Bubonic plague (termed ``barbarian boils'') sweeps China.
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ca. 166
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Antonine plague in Rome (possibly smallpox or bubonic plague) eventually kills millions throughout the weakening Roman empire.
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ca. 200
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Galen, the preeminent medical authority of late Antiquity and the Middle Ages, creates a philosophy of medicine, anatomy, and physiology that remains virtually unchallenged until the sixteenth and seventeenth centuries. Galen argues that embryological development is epigenetic, although he disagrees with Aristotle about which organs are formed first and which are most important.
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529
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Byzantine Emperor Justinian closes the Academy in Athens that was founded by Plato and forbids pagan scientists and philosophers to teach. This causes an exodus of scientists to Persia.
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ca. 980
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Abu Al-Qasim Al-Zahravi (Abucasis) creates a system and method of human dissection along with the first formal specific surgical techniques.
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ca. 1150
|
Hildegard of Bingen (1098–1179), Germanic author, publishes The Book of Simple Medicine, a treatise on the medicinal qualities of plants and minerals.
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ca. 1267
|
Roger Bacon (1214–1292), English philosopher and scientist, asserts that natural phenomena should be studied empirically.
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ca. 1275
|
William of Saliceto creates the first established record of a human dissection.
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1348
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The beginning of a three-year epidemic caused by Yersinia pestis that kills almost one-third of the population of urban Europe. In the aftermath of the epidemic, measures are introduced by the Italian government to improve public sanitation, marking the origin of public health.
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1490
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Leonardo da Vinci (1452–1519), Italian artist and scientist, describes patterns of capillary action.
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1492
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Venereal diseases, smallpox, and influenza brought by Columbus's expedition (and subsequent European explorers) to the New World. Millions of native peoples eventually die from these diseases because of a lack of prior exposure to stimulate immunity. In some regions, whole villages are wiped-out; and across broader regions, up to 95% of the native population dies as a result of exposure to these new pathogens.
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ca. 1525
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Paracelsus (1493–1541), Swiss physician and alchemist, uses mineral substances as medicines. Denying Galen's authority, Paracelsus teaches that life is a chemical process.
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1542
|
Bubonic plague from China devastates Constantinople before advancing to repeatedly kill millions across Europe.
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1543
|
Andreas Vesalius publishes his epoch-making treatise The Fabric of the Human Body Vesalius generally accepts Galenic physiological doctrines and ideas about embryology, but corrects many of Galen's misconceptions regarding the human body. Vesalius is subsequently recognized as the founder of modern anatomy.
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1546
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Gerolamo Fracastoro (1478–1553) writes a treatise on contagious diseases that identifies and names syphilis. He presents a rudimentary concept of the germ theory of disease.
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1568
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Zacharias and Hans Janssen develop the first compound microscope. The innovation opens new opportunities for the study of structural detail.
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1600
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Girolamo Fabrizzi (Fabricus ab Aquapendente) publishes De formato foetu On the formation of the fetus). The illustrations stir academic debate.
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1604
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German astronomer and mathematician Johannes Kepler (1571–1630) writes a treatise on optics.
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1610
|
Jean Beguin (1550–1620) publishes the first text-book on chemistry.
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1614
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Italian physician Santorio Santorio (1561–1636) publishes studies on metabolism.
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1628
|
William Harvey (1578–1657), English physician, publishes his Anatomical Treatise on the Movement of the Heart and Blood This scientific classic presents the first accurate description of blood circulation, tracing the course of blood through the heart, arteries, and veins.
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1651
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Harvey publishes On the Generation of Animals, , a treatise on embryology in which Harvey asserts that all living things come from eggs. He argues that oviparous and viviparous generation are analogous, but maintains support for the Aristotelian doctrine that generation occurs by epigenesis.
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1658
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Dutch naturalist Jan Swammerdam publishes records of observations of red blood cells.
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1660
|
Marcello Malpighi publishes his observations concerning vascular capillary beds and individual capillaries.
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1664
|
René Descartes (1596–1650), French philosopher and mathematician, publicizes his idea of reflexive action. The assertion is included in a French edition of his posthumously published work on animal physiology. In his analysis Descartes applies his mechanistic philosophy to the analysis of animal behavior; he first uses the concept of reflex to denote any involuntary response the body makes when exposed to a stimulus.
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1665
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Robert Hooke publishes Micrographia, an account of observations made with the new instrument known as the microscope. Hooke presents his drawings of the tiny box-like structures found in cork and calls these tiny structures ``cells.'' Although the cells he observes are not living, the name is retained. He also describes the streaming juices of live plant cells.
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1668
|
Francesco Redi publishes Experiments on the Generation of Insects, in which he demonstrates that maggots develop from eggs laid by flies. His observations disprove the theory that maggots are spontaneously generated from rotting meats.
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1669
|
Jan Swammerdam begins his pioneering work on the metamorphosis of insects and the anatomy of the mayfly. Swammerdam suggests that new individuals were embedded, or preformed, in their predecessors. Nicolas de Malebranche later reformulates Swammerdam's preformationist ideas into a more sophisticated philosophical doctrine that involves a series of embryos preexisting within each other like a nest of boxes.
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1674
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Antoni van Leeuwenhoek observes ``animalcules'' in lake water viewed through a ground glass lens. This observation of what will eventually be known as bacteria represents the start of the formal study of microbiology.
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1683
|
Antoni van Leeuwenhoek discovers different types of minute organisms he refers to as ``infusoria'' in decomposing matter and stagnant water. He also describes protozoa and bacteria.
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1700
|
Joseph Pitton de Tournefort presents an early version of the binomial method of classification, which is subsequently developed by Carl Linnaeus.
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1727
|
Hales studies plant nutrition and measures water absorbed by plant roots and released by leaves. He argues that something in the air (carbon dioxide) is converted into food, and that light is a necessary element of this process.
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1735
|
Carl Linnaeus publishes his Systema Naturae, or The Three Kingdoms of Nature Systematically Proposed in Classes, Orders, Genera, and Species, a methodical and hierarchical classification of all living beings. He develops the binomial nomenclature for the classification of plants and animals. In this system, each type of living being is classified in terms of genus (denoting the group to which it belongs) and species (its particular, individual name). His classification of plants is primarily based on the characteristics of their reproductive organs.
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1740
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Abraham Trembley asserts that the fresh water hydra, or ``polyp,'' appears to be an animal rather than a plant. When the hydra is cut into pieces, each part regenerates a complete new organism. These experiments raise many philosophical questions about the ``organizing principle'' in animals and the nature of development.
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1746
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Pierre-Louis Moreau de Maupertuis publishes Venus Physique. Maupertuis criticizes preformationist theories because offspring inherit characteristics of both parents. He proposes an adaptationist account of organic design. His theories suggests the existence of a mechanism for transmitting adaptations.
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1748
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Nollet describes osmosis.
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1754
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Pierre-Louis Moreau de Maupertuis suggests that species change over time, rather than remaining fixed.
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1757
|
Albrecht von Haller (1757–1766) publishes the first volume of his eight-volume Elements of Physiology of the Human Body subsequently to become a landmark in the history of modern physiology.
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1759
|
Kaspar Friedrich Wolff publishes Theory of Generation, which argues that generation occurs by epigenesis (the gradual addition of parts). This book marks the beginning of modern embryology.
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1762
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Marcus Anton von Plenciz, Sr. suggests that all infectious diseases are caused by living organisms and that there is a particular organism for each disease.
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1765
|
Abraham Trembley observes and publishes drawings of cell division in protozoans and algae.
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1765
|
Lazzaro Spallanzani publishes his Microscopical Observations. Spallanzani's experiments refutes the theory of the spontaneous generation of infusoria.
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1772
|
Joseph Priestley (1733–1804), an English theologian and chemist, discovers that plants give off oxygen.
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1774
|
Antoine-Laurent Lavoisier (1743–1794), a French chemist, discovers that oxygen is consumed during respiration.
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1779
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Jan Ingenhousz (1739–1799), Dutch physician and plant physiologist, publishes his Experiments upon Vegetables. He shows that light is necessary for the
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| |
production of oxygen, and that carbon dioxide is taken in by plants in the daytime and given off at night.
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1780
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Antoine-Laurent Lavoisier (1743–1794), French chemist, and Pierre-Simon Laplace (1749–1827), French astronomer and mathematician, collaborate to demonstrate that respiration is a form of combustion. Breathing, like combustion, liberates heat, carbon dioxide, and water.
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1780
|
George Adams (1750–1795), English engineer, engineers the first microtome. This mechanical instrument cuts thin slices for examination under a microscope, thus replacing the imprecise procedure of cutting with a hand-held razor.
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1789
|
Antoine-Laurent de Jussieu publishes his Plant Genera, a widely acclaimed book that incorporates the Linnaean system of binomial nomenclature. This book comes to be regarded as the foundation of the natural system of botanical classification. Jussieu classifies plants on the basis of cotyledons, and divides all plants into acotyledons, monocotyledons, and dicotyledons.
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1796
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Edward Jenner (1749–1823) uses cowpox virus to develop a smallpox vaccine.
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1796
|
Erasmus Darwin, grandfather of Charles Darwin and Francis Galton, publishes his Zoonomia. In this work, Darwin argues that evolutionary changes are brought about by the mechanism primarily associated with Jean-Baptiste Lamarck, i.e., the direct influence of the environment on the organism.
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1797
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Georges-Léopold-Chrétien-Frédéric Dagobert Cuvier establishes modern comparative zoology with the publication of his first book, Basic Outline for a Natural History of Animals. Cuvier studies the ways in which an animal's function and habits determine its form. He argues that form always followed function and that the reverse relationship did not occur.
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1798
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Government legislation is passed to establish hospitals in the United States devoted to the care of ill mariners. This initiative leads to the establishment of a Hygenic Laboratory that eventually grows to become the National Institutes of Health.
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|
1800
|
Marie-François-Xavier Bichat publishes his first major work, Treatise on Tissues, which establishes histology as a new scientific discipline. Bichat distinguishes 21 kinds of tissue and relates particular diseases to particular tissues.
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1802
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Jean-Baptiste-Pierre-Antoine de Monet de Lamarck and Gottfried Reinhold Treviranus propose the term ldquo;biology'' to denote a new general science of living beings that would supercede studies in natural history.
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1802
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John Dalton introduces modern atomic theory into the science of chemistry.
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1809
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Jean-Baptiste-Pierre-Antoine de Monet de Lamarck introduces the term ``invertebrate'' in his Zoological Philosophy, which contains the first influential scientific theory of evolution. He attempts to classify organisms by function rather than by structure and is the first to use genealogical trees to show relationships among species.
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1812
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Kirchoff identifies catalysis and mechanisms of catalytic reactions.
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1817
|
Georges-Léopold-Chrétien-Frédéric Dagobert Cuvier publishes his major work, The Animal Kingdom, which expands and improves Linnaeus's classification system. Cuvier groups related classes into a broader category called a phylum. He is also the first to extend this system of classification to fossils.
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1818
|
William Charles Wells suggests the theory of natural selection in an essay dealing with human color variations. He notes that dark skinned people are more resistant to tropical diseases than lighter skinned people. Wells also calls attention to selection carried out by animal breeders. Jerome Lawrence, James Cowles Prichard, and others make similar suggestions, but do not develop their ideas into a coherent and convincing theory of evolution.
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1820
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First United States Pharmacopoeia is published.
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1824
|
René–Joachim-Henri Dutrochet suggests that tissues are composed of living cells.
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1826
|
James Cowles Prichard presents his views on evolution in the second edition of his book Researches into the Physical History of Man first edition 1813). These ideas about evolution are suppressed in later editions.
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1828
|
Friedrich Wöhler synthesizes urea. This is generally regarded as the first organic chemical produced in the laboratory, and an important step in disproving the idea that only living organisms can produce organic compounds. Work by Wöhler and others establish the foundations of organic chemistry and biochemistry.
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1828
|
Karl Ernst von Baer publishes a book entitled On the Developmental History of Animals 2 volumes, 1828–1837), in which he demonstrates that embryological development follows essentially the same pattern in a wide variety of mammals. Early mammalian embryos are very similar, but they diverge at later stages of gestation. Von Baer's work establishes the modern field of comparative embryology.
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1828
|
Robert Brown observes a small body within the cells of plant tissue and calls it the ``nucleus.'' He
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| |
also discovers what becomes known as ``Brownian movement.''
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1831
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Charles Robert Darwin begins his historic voyage on the H.M.S. Beagle 1831–1836). His observations during the voyage lead to his theory of evolution by means of natural selection.
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1831
|
Patrick Matthew includes a discussion of evolution and natural selection in his book On Naval Timber and Arboriculture. Matthew later claims priority in the discovery of evolution by means of natural selection in an article published in 1860 in the journal Gardeners' Chronicle.
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1832
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The French physiologist Anselme Payen 1795–1871) isolates diastase from barley. Diastase catalyzes the conversion of starch into sugar, and is an example of the organic catalysts within living tissue that eventually come to be called enzymes.
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1836
|
Félix Dujardin describes the ``living jell'' of the cytoplasm, which he calls ``sarcode.''
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1836
|
Theodor Schwann carries out experiments that refute the theory of the spontaneous generation of infusoria. He also demonstrates that alcoholic fermentation depends on the action of living yeast cells. The same conclusion is reached independently by Charles Caignard de la Tour.
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1837
|
French physiologist René–Joachim Dutrochet 1776–1847) publishes his research on plant physiology that includes pioneering work on osmosis. He is the first scientist to systematically investigate the process of osmosis, which he names, and to argue that chlorophyll is necessary for photosynthesis.
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1838
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Matthias Jakob Schleiden notes that the nucleus first described by Robert Brown is a characteristic of all plant cells. Schleiden describes plants as a community of cells and cell products. He helps establish cell theory and stimulates Theodor Schwann's recognition that animals are also composed of cells and cell products.
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1839
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Jan Evangelista Purkinje uses the term ``protoplasm'' to describe the substance within living cells.
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1839
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Theodore Schwann extends the theory of cells to include animals and helps establish the basic unity of the two great kingdoms of life. He publishes Microscopical Researches into the Accordance in the Structure and Growth of Animals and Plants in which he asserts that all living things are made up of cells and that each cell contains certain essential components. He also coins the term ``metabolism'' to describe the overall chemical changes that take place in living tissues.
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1840
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Friedrich Gustav Jacob Henle publishes the first histology textbook, General Anatomy. This work includes the first modern discussion of the germ theory of communicable diseases.
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1840
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German chemist Justus von Liebig (1803–1873) shows that plants synthesize organic compounds from carbon dioxide in the air but take their nitrogenous compounds from the soil. He also states that ammonia (nitrogen) is needed for plant growth.
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1840
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Karl Bogislaus Reichert introduces the cell theory into the discipline of embryology. He proves that the segments observed in fertilized eggs develop into individual cells, and that organs develop from cells.
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1842
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Charles Robert Darwin writes out an abstract of his theory of evolution, but he does not plan to have this theory published until after his death.
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1842
|
Theodor Ludwig Wilhelm Bischoff publishes the first textbook of comparative embryology, Developmental History of Mammals and Man.
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1844
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Robert Chambers anonymously publishes Vestiges of the Natural History of Creation, which advocates the theory of evolution. This controversial book becomes a best seller and introduces the general reading public to the theory of evolution.
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1845
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Karl Theodor Ernst von Siebold realizes that protozoa are single-celled organisms. He is the first scientist to define protozoa as organisms.
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1847
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A series of yellow fever epidemics sweeps the American Southern states. The epidemics recur every few years for more than 30 years.
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1851
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Hugo von Mohl publishes his Basic Outline of the Anatomy and Physiology of the Plant Cell, in which he proposes that new cells are created by cell division.
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1854
|
Gregor Mendel begins to study 34 different strains of peas. He selects 22 kinds for further experiments. From 1856 to 1863, Mendel grows and tests over 28,000 plants and analyzes seven pairs of traits.
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1855
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Alfred Russell Wallace writes an essay entitled On the Law Which has Regulated the Introduction of New Species and sends it to Charles Darwin. Wallace's essay and one by Darwin are published in the 1858 Proceedings of the Linnaean Society.
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1857
|
Louis Pasteur demonstrates that lactic acid fermentation is caused by a living organism. Between 1857 and 1880 he performs a series of experiments that refute the doctrine of spontaneous generation. He also introduces vaccines for fowl cholera, anthrax, and rabies, based on attenuated strains of viruses and bacteria.
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1858
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Charles Darwin and Alfred Russell Wallace agree to a joint presentation of their theory of evolution by natural selection.
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1858
|
Rudolf Ludwig Carl Virchow publishes his landmark paper ``Cellular Pathology,'' thus establishing the field of that name. Virchow asserts that all cells arise from preexisting cells (Omnis cellula e cellula). He argues that the cell is the ultimate locus of all disease.
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1859
|
Charles Robert Darwin publishes his landmark book On the Origin of Species by Means of Natural Selection.
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1860
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Ernst Heinrich Haeckel describes the essential elements of modern zoological classification.
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1860
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Louis Pasteur carries out experiments that disprove the doctrine of spontaneous generation.
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1860
|
Max Johann Sigismund Schultze describes the nature of protoplasm and shows that it is fundamentally the same for all life forms.
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1863
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Thomas Henry Huxley publishes Evidence As to Man's Place in Nature, which extends Darwin's theory of evolution to include humans. Huxley becomes the champion and defender of Darwinism in England.
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1865
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An epidemic of rinderpest kills 500,000 cattle in Great Britain. Government inquiries into the outbreak pave the way for the development of contemporary theories of epidemiology and the germ theory of disease.
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1865
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Gregor Mendel presents his work on hybridization of peas to the Natural History Society of Brno, Czechoslovakia. The paper is published in the 1866 issue of the Society's Proceedings. Mendel presents statistical evidence that hereditary factors are inherited from both parents in a series of papers on ldquo;Experiments on Plant Hybridization'' published between 1866 and 1869. Although his experiments provide evidence of dominance, the laws of segregation, and independent assortment, his work is generally ignored until 1900.
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1866
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Ernst Heinrich Haeckel publishes his book A General Morphology of Organisms. Haeckel summarizes his ideas about evolution and embryology in his famous—though long-discredited—dictum ``ontogeny recapitulates phylogeny'' (or, the development of an individual organism follows the same stages as the development of its species). He suggests that the nucleus of a cell transmits hereditary information and introduces the term ``ecology'' to describe the study of living organisms and their interactions with other organisms and with their environment.
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1866
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The Austrian botanist and monk Johann Gregor Mendel (1822–1884) discovers the laws of heredity and writes the first of a series of papers on the subject (1866–1869). The papers formulate the laws of hybridization. Mendel's work is disregarded until 1900, when de Vries rediscovers it. Unbeknownst to both Darwin and Mendel, Mendelian laws provide the scientific framework for the concepts of gradual evolution and continuous variation.
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1867
|
Robert Koch establishes the role of bacteria in anthrax, providing the final piece of evidence in support of the germ theory of disease. Koch goes on to formulate postulates that, when fulfilled, confirm bacteria or viruses as the cause of an infection.
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1868
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Charles Darwin publishes The Variation of Animals and Plants under Domestication (2 volumes).
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1868
|
Thomas Henry Huxley introduces the term ``protoplasm'' to the general public in a lecture entitled ``The Physical Basis of Life.''
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1869
|
Johann Friedrich Miescher discovers nuclein, a new chemical isolated from the nuclei of pus cells. Two years later he isolates nuclein from salmon sperm. This material comes to be known as nucleic acid.
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1870
|
Thomas Huxley delivers a speech that introduces the terms biogenesis (life from life) and abiogenesis (life from non-life; spontaneous generation). The speech strongly supports Pasteur's claim to have refuted the concept of spontaneous generation.
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1871
|
Charles Robert Darwin publishes The Descent of Man, and Selection in Relation to Sex. This work introduces the concept of sexual selection and expands his theory of evolution to include humans.
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1871
|
Ferdinand Julius Cohn coins the term bacterium.
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1872
|
Franz Anton Schneider observes and describes the behavior of nuclear filaments (chromosomes) during cell division in his study of the platyhelminth Mesostoma. His account is the first accurate description of the process of mitosis in animal cells.
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1873
|
Camilo Golgi discovers that tissue samples can be stained with an inorganic dye (silver salts). Golgi uses this method to analyze the nervous system and characterizes the cells known as Golgi Type I and Golgi Type II cells and the ``Golgi Apparatus.'' Golgi is subsequently awarded a Nobel Prize in 1906 for his studies of the nervous system.
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1873
|
Franz Anton Schneider describes cell division in detail. His drawings include both the nucleus and chromosomal strands.
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1873
|
Walther Flemming discovers chromosomes, observes mitosis, and suggests the modern interpretation of nuclear division.
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1874
|
Wilhelm August Oscar Hertwig concludes that fertilization in both animals and plants consists of the physical union of the two nuclei contributed by the male and female parents. Hertwig subsequently carries out pioneering studies of reproduction of the sea urchin.
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1875
|
Eduard Adolf Strasburger publishes Cell-Formation and Cell-Division, in which he describes nuclear division in plants. Strasburger accurately describes the process of mitosis and argues that new nuclei can only rise from the division of preexisting nuclei. His treatise helps establish cytology as a distinct branch of histology.
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1875
|
Ferdinand Cohn publishes a classification of bacteria in which the genus name Bacillus is used for the first time.
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1876
|
Edouard G. Balbiani observes the formation of chromosomes.
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1876
|
Robert Koch publishes a paper on anthrax that implicates a bacterium as the cause of the disease, validating the germ theory of disease
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1877
|
Robert Koch describes new techniques for fixing, staining, and photographing bacteria.
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1877
|
Paul Erlich recognizes the existence of the mast cells of the immune system.
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1877
|
Wilhelm Friedrich Kühne proposes the term enzyme (meaning ``in yeast''). Kühne establishes the critical distinction between enzymes, or ``ferments,'' and the microorganisms that produce them.
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1878
|
Charles-Emanuel Sedillot introduces the term ``microbe.'' The term becomes widely used as a term for a pathogenic bacterium.
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1878
|
Joseph Lister publishes a paper describing the role of a bacterium he names Bacterium lactis in the souring of milk.
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1878
|
Thomas Burrill demonstrates for the first time that a plant disease (pear blight) is caused by a bacterium (Micrococcus amylophorous).
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1879
|
Albert Nisser identifies Neiserria gonorrhoeoe as the cause of gonorrhea.
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|
1879
|
Walther Flemming describes and names chromatin, mitosis, and the chromosome threads. Fleming's drawings of the longitudinal splitting of chromosomes in eukaryotic cells provide the first accurate counts of chromosome numbers.
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|
1880
|
C. L. Alphonse Laveran isolates malarial parasites in erythrocytes of infected people and demonstrates that the organism can replicate in the cells. He is awarded the 1907 Nobel Prize in Medicine or Physiology for this work.
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|
1880
|
Louis Pasteur develops a method of weakening a microbial pathogen of chicken, and uses the term ``attenuated'' to describe the weakened microbe.
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|
1880
|
The first issue of the journal Science is published by the American Association for the Advancement of Science.
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|
1880
|
Walther Flemming, Eduard Strasburger, Edouard van Beneden, and others document the basic outlines of cell division and the distribution of chromosomes to the daughter cells.
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|
1881
|
Eduard Strasburger coins the terms cytoplasm and nucleoplasm.
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1881
|
Walther Flemming discovers the lampbrush chromosomes.
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1882
|
Angelina Fannie and Walter Hesse in Koch's laboratory develop agar as a solid growth medium for microorganisms. Agar replaces gelatin as the solid growth medium of choice in microbiology.
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1882
|
Edouard van Beneden outlines the principles of genetic continuity of chromosomes in eukaryotic cells and reports the occurrence of chromosome reduction during the formation of the germ cells.
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|
1882
|
Pierre Émile Duclaux suggest that enzymes should be named by adding the suffix ``ase'' to the name of their substrate.
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1882
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The German bacteriologist Robert Koch (1843–1910) discovers the tubercle bacillus and enumerates ``Koch's postulates,'' which define the classic method of preserving, documenting, and studying bacteria.
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1882
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Walther Flemming publishes Cell Substance, Nucleus, and Cell Division, in which he describes his observations of the longitudinal division of chromosomes in animal cells. Flemming observes chromosome threads in the dividing cells of salamander larvae.
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1882
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Wilhelm Roux offers a possible explanation for the function of mitosis.
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1883
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August F. Weismann begins work on his germplasm theory of inheritance. Between 1884 and 1888, Weismann formulates the germplasm theory that asserts that the germplasm was separate and distinct from the somatoplasm. He argues that the germplasm was continuous from generation to generation and that only changes in the germplasm were transmitted to further generations. Weismann proposes a theory of chromosome behavior during cell division and fertilization and predicts the occurrence of a reduction division (meiosis) in all sexual organisms.
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1883
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Edward Theodore Klebs and Frederich Loeffler independently discover Corynebacterium diphtheriae, the bacterium that causes diphtheria.
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1883
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Walther Flemming, Eduard Strasburger and Edouard Van Beneden demonstrate that, in eukaryotic cells, chromosome doubling occurs by a process of longitudinal splitting. Strasburger describes and names the prophase, metaphase, and anaphase stages of mitosis.
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1883
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Wilhelm Roux suggests that chromosomes carry the hereditary factors.
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1884
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Elie Metchnikoff discovers the antibacterial activity of white blood cells, which he calls ``phagocytes,'' and formulates the theory of phagocytosis. He also develops the cellular theory of vaccination.
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1884
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Hans Christian J. Gram develops the Gram stain.
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1884
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Louis Pasteur and coworkers publish a paper entitled ``A New Communication on Rabies.'' Pasteur proves that the causal agent of rabies can be attenuated and the weakened virus can be used as a vaccine to prevent the disease. This work serves as the basis of future work on virus attenuation, vaccine development, and the concept that variation is an inherent characteristic of viruses.
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1884
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Oscar Hertwig, Eduard Strasburger, Albrecht von Kölliker, and August Weismann independently report that the cell nucleus serves as the basis for inheritance.
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1885
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Francis Galton devise a new statistical tool, the correlation table.
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1885
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French chemist Louis Pasteur (1822–1895) inoculates a boy, Joseph Meister, against rabies. Meister had been bitten by an infected dog. The treatment saves his life. This is the first time Pasteur uses an attenuated germ on a human being.
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1885
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Paul Ehrlich proposes that certain chemicals such as arsenic are toxic to bacteria.
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1885
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Theodor Escherich identifies a bacterium inhabiting the human intestinal tract that he names Bacterium coli and shows that the bacterium causes infant diarrhea and gastroenteritis. The bacterium is subsequently named Escherichia coli.
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1886
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Adolf Mayer publishes the landmark article ``Concerning the Mosaic Disease of Tobacco.'' This paper is considered the beginning of modern experimental work on plant viruses. Mayer assumes that the causal agent is a bacterium, though he is unable to isolate it.
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1887
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Julius Richard Petri develops a culture dish that has a lid to exclude airborne contaminants. The innovation is subsequently termed the Petri plate.
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1888
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Heinrich Wilhelm Gottfried Waldeyer coins the term ``chromosome.'' Waldeyer also introduces the use of hematoxylin as a histological stain.
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1888
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Martinus Beijerinck uses a growth medium enriched with certain nutrients to isolate the bacterium Rhizobium, demonstrating that nutritionally tailored growth media are useful in bacterial isolation.
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1888
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The Institute Pasteur is formed in France.
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1889
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Richard Altmann develops a method of preparing nuclein that is apparently free of protein. He calls his protein-free nucleins ``nucleic acids.''
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1889
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Theodor Boveri and Jean-Louis-Léon Guignard establish the numerical equality of the paternal and maternal chromosomes at fertilization.
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1891
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Charles-Edouard Brown-Sequard suggests the concept of internal secretions (hormones).
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1891
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Paul Ehrlich proposes that antibodies are responsible for immunity.
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1891
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Robert Koch proposes the concept of delayed type hypersensitivity.
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1892
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August Weismann publishes his landmark treatise The Germ Plasm: A Theory of Heredity, which emphasizes the role of meiosis in the distribution of chromosomes during the formation of gametes.
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1892
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Dmitri Ivanowski demonstrates that filterable material causes tobacco mosaic disease. The infectious agent is subsequently showed to be the tobacco mosaic virus. Ivanowski's discovery creates the field of virology.
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1892
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George M. Sternberg publishes his Practical Results of Bacteriological Researches. Sternberg's realization that a specific antibody was produced after infection with vaccinia virus and that immune serum could neutralize the virus becomes the basis of virus serology. The neutralization test provides a technique for diagnosing viral infections, measuring the immune response, distinguishing antigenic similarities and differences among viruses, and conducting retrospective epidemiological surveys.
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1893
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William Bateson publishes Materials for the Study of Variation, which emphasizes the importance of discontinuous variations (the kinds of variation studied by Mendel).
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1894
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Alexandre Yersin isolates Yersinia (Pasteurella) pestis, the bacterium responsible for bubonic plague.
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1894
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Wilhelm Konrad Roentgen discovers x rays.
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1897
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John Jacob Abel (1857–1938), American physiologist and chemist, isolates epinephrine (adrenalin). This is the first hormone to be isolated.
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1898
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Carl Benda discovers and names mitochondria, the subcellular entities previously seen by Richard Altmann.
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1898
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Friedrich Loeffler and Paul Frosch publish their Report on Foot-and-Mouth Disease. They prove that this animal disease is caused by a filterable virus and suggests that similar agents might cause other diseases.
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1898
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Martin Wilhelm Beijerinck publishes his landmark paper ``Concerning a Contagium Vivum Fluidum as Cause of the Spot Disease of Tobacco Leaves.'' Beijerinck thinks that the etiological agent, which could pass through a porcelain filter that removed known bacteria, might be a new type of invisible organism that reproduced within the cells of diseased plants. He realizes that a very small amount of the virus could infect many leaves and that the diseased leaves could infect others.
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1898
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The First International Congress of Genetics is held in London.
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1899
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A meeting to organize the Society of American Bacteriologists is held at Yale University. The society will later become the American Society for Microbiology.
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1899
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Jacques Loeb proves that it is possible to induce parthenogenesis in unfertilized sea urchin eggs by means of specific environmental changes.
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1900
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Carl Correns, Hugo de Vries, and Erich von Tschermak independently rediscover Mendel's laws of inheritance. Their publications mark the beginning of modern genetics. Using several plant species, de Vries and Correns perform breeding experiments that parallel Mendel's earlier studies and independently arrive at similar interpretations of their results. Therefore, upon reading Mendel's publication, they immediately recognized its significance. William Bateson describes the importance of Mendel's contribution in an address to the Royal Society of London.
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1900
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Hugo Marie de Vries describes the concept of genetic mutations in his book Mutation Theory. He uses the term mutation to describe sudden, spontaneous, drastic alterations in the hereditary material.
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1900
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Karl Landsteiner discovers the blood-agglutination phenomenon and the four major blood types in humans.
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1900
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Karl Pearson develops the chi-square test.
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1900
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Walter Reed demonstrates that Yellow Fever is caused by a virus transmitted by mosquitoes. This is the first demonstration of a viral cause of a human disease.
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1900
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Paul Erlich proposes the theory concerning the formation of antibodies by the immune system.
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1901
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Jules Bordet and Octave Gengou develop the complement fixation test.
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1901
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Theodor Boveri discovers that in order for sea urchin embryos to develop normally, they must have a full set of chromosomes. He concludes that the individual chromosomes must carry different hereditary determinants.
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1901
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William Bateson coins the terms genetics, F1 and F2 generations, allelomorph (later shortened to allele), homozygote, heterozygote, and epistasis.
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1902
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Carl Neuberg introduces the term biochemistry.
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1903
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Archibald Edward Garrod provides evidence that errors in genes caused several hereditary disorders in human beings. His 1909 book The Inborn Errors of Metabolism is the first treatise in biochemical genetics.
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1903
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Ruska develops a primitive electron microscope.
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1903
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Tiselius offers electrophoresis techniques that become the basis for the separation of biological molecules by charge, mass, and size.
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1903
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Walter S. Sutton publishes a paper in which he presents the chromosome theory of inheritance. The theory, which states that the hereditary factors are located in the chromosomes, is independently proposed by Theodor Boveri and is generally referred to as the Sutton-Boveri hypothesis.
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1906
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Viennese physician and immunological researcher Clemens von Pirquet (1874–1929) coins the term allergy to describe the immune reaction to certain compounds.
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1909
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Phoebus Aaron Theodore Levene (1869–1940), Russian-American chemist, discovers the chemical difference between DNA (deoxyribonucleic acid) and RNA (ribonucleic acid).
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1909
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Sigurd Orla-Jensen proposes that the physiological reactions of bacteria are primarily important in their classification.
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1909
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Wilhelm Ludwig Johannsen argues the necessity of distinguishing between the appearance of an organism and its genetic constitution. He invents the terms ``gene'' (carrier of heredity), ``genotype'' (an organism's genetic constitution), and ``phenotype'' (the appearance of the actual organism).
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1911
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Peyton Rous publishes the landmark paper ``Transmission of a Malignant New Growth by Means of a Cell-Free Filtrate.'' His work provides the first rigorous proof of the experimental transmission
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of a solid tumor and suggests that a filterable virus is the causal agent.
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1912
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Casimir Funk (1884–1967), Polish-American biochemist, coins the term ``vitamine.'' Since the dietary substances he discovers are in the amine group he calls all of them ``life-amines'' (using the Latin word vita for ``life'').
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1912
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The United States Public Health Service is established.
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1912
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Paul Ehrlich discovers a chemical cure for syphilis. This is the first chemotherapeutic agent for a bacterial disease.
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1914
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Frederick William Twort (1877–1950), English bacteriologist, and Felix H. D'Herelle (1873–1949), Canadian-Russian physician, independently discover bacteriophage.
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1914
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Thomas Hunt Morgan, Alfred Henry Sturtevant, Calvin Blackman Bridges, and Hermann Joseph Muller publish the classic treatise of modern genetics, The Mechanism of Mendelian Heredity.
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1915
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Frederick William Twort publishes the landmark paper ``An Investigation of the Nature of Ultra-Microscopic Viruses.'' Twort notes the degeneration of bacterial colonies and suggests that the causative agent is an ultra-microscopic-filterable virus that multiplies true to type.
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1915
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Katherine K. Sanford isolates a single mammalian cell in vitro and allows it to propagate to form identical descendants. Her clone of mouse fibroblasts is called L929, because it took 929 attempts before a successful propagation was achieved. Sanford's work is an important step in establishing pure cell lines for biomedical research.
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1916
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Felix Hubert D'Herelle carries out further studies of the agent that destroys bacterial colonies and gives it the name ``bacteriophage'' (bacteria eating agent). D'Herelle and others unsuccessfully attempted to use bacteriophages as bactericidal therapeutic agents.
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1917
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D'Arcy Wentworth Thompson publishes On Growth and Form, which suggests that the evolution of one species into another occurs as a series of transformations involving the entire organism, rather than a succession of minor changes in parts of the body.
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1918
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Calvin B. Bridges discovers chromosomal duplications in Drosophila.
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1918
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More people are killed in a global influenza pandemic than soldiers die fighting World War I. By the end of 1918, approximately 25 million people die from a virulent strain of Spanish influenza.
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1919
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James Brown uses blood agar to study the destruction of blood cells by the bacterium Streptococcus. He observes three reactions that he designates alpha, beta, and gamma.
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1919
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The Health Organization of the League of Nations is established for the prevention and control of disease around the world.
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1924
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Albert Jan Kluyver publishes Unity and Diversity in the Metabolism of Micro-organisms He demonstrates that different microorganisms have common metabolic pathways of oxidation, fermentation, and synthesis of certain compounds. Kluyver also states that life on Earth depends on microbial activity.
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1926
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Bernard O. Dodge begins genetic studies on Neurospora.
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1926
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Thomas C. Vanterpool publishes a paper that clarifies the problem of ``mixed infections'' of plant viruses. His study of the condition known as ``streak'' or ``winter blight'' of tomatoes shows that it was the result of simultaneous infection of tomato plants by tomato mosaic virus and a potato mosaic virus.
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1927
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Hermann Joseph Muller induces artificial mutations in fruit flies by exposing them to x rays. His work proves that mutations result from some type of physicalchemical change. Muller goes on to write extensively about the danger of excessive x rays and the burden of deleterious mutations in human populations.
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1927
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Thomas Rivers publishes a paper that differentiates bacteria from viruses, establishing virology as a field of study that is distinct from bacteriology.
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1928
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Fred Griffith discovers that certain strains of pneumococci could undergo some kind of transmutation of type. After injecting mice with living R type pneumococci and heat-killed S type, Griffith is able to isolate living virulent bacteria from the infected mice. Griffith suggests that some unknown ``principle'' had transformed the harmless R strain of the pneumococcus to the virulent S strain.
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1929
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Francis O. Holmes introduces the technique of ``local lesion'' as a means of measuring the concentration of tobacco mosaic virus. The method becomes extremely important in virus purification.
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1929
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Frank M. Burnet and Margot McKie report critical insights into the phenomenon known as lysogeny (the inherited ability of bacteria to produce bacteriophage in the absence of infection). Burnet and McKie postulate that the presence of a ``lytic unit'' as a normal hereditary component of lysogenic bacteria. The ``lytic unit'' is proposed to be capable of liberating bacteriophage when it is activated by certain conditions. This concept is confirmed in the 1950s.
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1929
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Scottish biochemist Alexander Fleming (1881–1955) discovers penicillin. He observes that the mold Penicillium notatum inhibits the growth of some bacteria. This is the first anti-bacterial, and it opens a new era of ``wonder drugs'' to combat infection and disease.
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1930
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Curt Stern, and, independently, Harriet B. Creighton and Barbara McClintock, demonstrate cytological evidence of genetic crossing over between eukaryotic chromosomal strands.
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1930
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Max Theiler demonstrates the advantages of using mice as experimental animals for research on animal viruses. Theiler uses mice in his studies of the yellow fever virus.
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1931
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Phoebus A. Levene publishes a book that summarizes his work on the chemical nature of the nucleic acids. His analyses of nucleic acids seemed to support the hypothesis known as the tetranucleotide interpretation, which suggests that the four bases are present in equal amounts in DNAs from all sources. Perplexingly, this indicated that DNA is a highly repetitious polymer that is incapable of generating the diversity that would be an essential characteristic of the genetic material.
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1932
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William J. Elford and Christopher H. Andrewes develop methods of estimating the sizes of viruses by using a series of membranes as filters. Later studies prove that the viral sizes obtained by this method were comparable to those obtained by electron microscopy.
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1934
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John Marrack begins a series of studies that leads to the formation of the hypothesis governing the association between an antigen and the corresponding antibody.
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1935
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Wendall Meredith Stanley (1904–1971), American biochemist, discovers that viruses are partly proteinbased. By purifying and crystallizing viruses, he enables scientists to identify the precise molecular structure and propagation modes of several viruses. Stanley wins the Nobel Prize in Chemistry in 1946.
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1936
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George P. Berry and Helen M. Dedrick report that the Shope virus could be ``transformed'' into Myxomatosis/Sanarelli virus. This virological curiosity was variously referred to as ``transformation,'' ``recombination,'' and ``multiplicity of reactivation.'' Subsequent research suggests that it is the first example of genetic interaction between animal viruses, but some scientists warn that the phenomenon might indicate the danger of reactivation of virus particles in vaccines and in cancer research.
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1936
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Theodosius Dobzhansky publishes Genetics and the Origin of Species, a text eventually considered a classic in evolutionary genetics.
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1937
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Hans Adolf Krebs (1900–1981), German biochemist, describes and names the citric acid cycle.
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1938
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Emory L. Ellis and Max Delbrück perform studies on phage replication that mark the beginning of modern phage work. They introduce the ``one-step growth'' experiment, which demonstrates that after bacteriophages attack bacteria, replication of the virus occurs within the bacterial host during a ``latent period,'' after which viral progeny are released in a ``burst.''
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1939
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Richard E. Shope reports that the swine influenza virus survived between epidemics in an intermediate host. This discovery is an important step in revealing the role of intermediate hosts in perpetuating specific diseases.
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1939
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Ernest Chain and H. W. Florey refine the purification of penicillin, making possible the mass production of the antibiotic.
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1940
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Ernest Chain and E. P. Abraham detail the inactivation of penicillin by a substance produced by Escherichia coli. This is the first bacterial compound known to produce resistance to an antibacterial agent.
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1940
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Helmuth Ruska obtains the first electron microscopic image of a virus.
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1941
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George W. Beadle and Edward L. Tatum publish their classic study on biochemical genetics entitled Genetic Control of Biochemical Reactions in Neurospora. Beadle and Tatum irradiate red bread mold Neurospora and prove that genes produce their effects by regulating particular enzymes. This work leads to the one gene–one enzyme theory.
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1941
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Lipmann describes and identifies the biochemical and physiological role of high energy phosphates (e.g., adenosine triphosphate; ATP).
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1942
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Jules Freund and Katherine McDermott identify adjuvants (e.g., paraffin oil) that act to boost antibody production.
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1942
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Salvador E. Luria and Max Delbrück demonstrate statistically that inheritance of genetic characteristics in bacteria follows the principles of genetic inheritance proposed by Charles Darwin. For their work the two (along with Alfred Day Hershey) are awarded the 1969 Nobel Prize in Medicine or Physiology.
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1942
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Salvador E. Luria and Thomas F. Anderson publish the first electron micrographs of bacterial viruses. The Escherichia coli bacteriophage appears to have a round, or polyhedral head and a thin tail.
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1942
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Selman Waksman suggests that the word ``antibiotics'' be used to identify antimicrobial compounds that are made by bacteria.
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1944
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New techniques and instruments, such as partition chromatography on paper strips and the photoelectric ultraviolet spectrophotometer, stimulate the development of biochemistry after World War II. New methodologies make it possible to isolate, purify, and identify many important biochemical substances, including the purines, pyrimidines, nucleosides, and nucleotides derived from nucleic acids.
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1944
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Oswald T. Avery, Colin M. MacLeod, and Maclyn McCarty publish a landmark paper on the pneumococcus transforming principle. The paper is entitled ``Studies on the chemical nature of the substance inducing transformation of pneumococcal types.'' Avery suggests that the transforming principle seems to be deoxyribonucleic acid (DNA), but contemporary ideas about the structure of nucleic acids suggest that DNA does not possess the biological specificity of the hypothetical genetic material.
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1944
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Salvador E. Luria and Alfred Day Hershey prove that mutations occur in bacterial viruses, and they develop methods to distinguish the mutations from other alterations.
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1945
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Joshua Lederberg and Edward L. Tatum demonstrate genetic recombination in bacteria.
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1945
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Max Delbrück organizes the first session of the phage course at Cold Spring Harbor Laboratory. The widely influential phage course, which is subsequently taught for 26 consecutive years, serves as the training center for the first two generations of molecular biologists
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1946
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James B. Sumner, John H. Northrop, and Wendell M. Stanley receive the Nobel Prize in Chemistry for their independent work on the purification and crystallization of enzymes and viral proteins.
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1946
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Joshua Lederberg and Edward L. Tatum demonstrate that genetic recombination occurs in bacteria as the result of sexual mating. Lederberg and Tatum announce their discovery at the 1946 Cold Spring Harbor Symposium on Microbial Genetics, an event that becomes recognized as a landmark in the development of molecular biology.
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1946
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Max Delbrück and W. T. Bailey, Jr. publish a paper entitled ``Induced Mutations in Bacterial Viruses.'' Despite some confusion about the nature of the phenomenon in question, this paper establishes the fact that genetic recombinations occur during mixed infections with bacterial viruses. Alfred Hershey and R. Rotman make the discovery of genetic recombination in bacteriophage simultaneously and independently. Hershey and his colleagues prove that this phenomenon can be used for genetic analyses. They construct a genetic map of phage particles and show that phage genes can be arranged in a linear fashion.
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1947
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Joshua Lederberg and Norton Zinder, and, independently, Bernard D. Davis, develop the penicillin-selection technique for isolating biochemically deficient bacterial mutants.
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1948
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Barbara McClintock publishes her research on transposable regulatory elements (``jumping genes'') in maize. Her work was not appreciated until similar phenomena were discovered in bacteria and fruit flies in the 1960s and 1970s. McClintock was awarded the Nobel Prize in Medicine or Physiology in 1983.
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1948
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World Health Organization is formed. The WHO subsequently becomes the principle international organization managing public health related issues on a global scale. Headquartered in Geneva, the WHO becomes, by 2002, an organization of more than 190 member countries. The organization contributes to international public health in areas including disease prevention and control, promotion of good health, addressing disease outbreaks, initiatives to eliminate diseases (e.g., vaccination programs), and development of treatment and prevention standards.
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1949
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John F. Ender, Thomas H. Weller, and Frederick C. Robbins publish ``Cultivation of Polio Viruses in Cultures of Human Embryonic Tissues.'' The report is a landmark in establishing techniques for the cultivation of poliovirus in cultures on non-neural tissue and for further virus research. The technique leads to the polio vaccine and other advances in virology.
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1949
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The role of mitochondria is finally revealed. These slender filaments within the cell, which participate in protein synthesis and lipid metabolism, are the cell's source of energy.
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1949
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Macfarlane Burnet and his colleagues begin studies that lead to the immunological tolerance hypothesis and the clonal selection theory. Burnet receives the 1960 Nobel Prize in Physiology or Medicine for this research.
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1950
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British physician Douglas Bevis demonstrates that amniocentesis could be used to test fetuses for Rhfactor incompatibility.
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1950
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Erwin Chargaff demonstrates that the Tetranucleotide Theory is incorrect and that DNA is more complex than the model developed by Phoebus A. Levene. Chargaff proves that the nucleic acids are not monotonous polymers. Chargaff also discovers interesting regularities in the base composition of DNA; these findings are later known as ``Chargaff's rules.'' Chargaff discovers a one-to-one ratio of adenine to thymine and guanine to cytosine in DNA samples from a variety of organisms.
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1950
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Robert Hungate develops the roll-tube culture technique, which is the first technique that allows anaerobic bacteria to be grown in culture.
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1950
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Ruth Sager's work on the algae Chlamydomonas proves that cytoplasmic genes exist and that they can undergo mutation. She shows that such genes can be mapped on a ``cytoplasmic chromosome.'' Confirmation is provided when other researchers report similar findings in yeast and Neurospora,. Subsequently the DNA is shown to be associated with cytoplasmic organelles.
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1951
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Esther M. Lederberg discovers a lysogenic strain of Escherichia coli K12 and isolates a new bacteriophage, called lambda.
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1951
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Rosalind Franklin obtains sharp x-ray diffraction photographs of deoxyribonucleic acid.
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1952
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Alfred Hershey and Martha Chase publish their landmark paper ``Independent Functions of Viral Protein and Nucleic Acid in Growth of Bacteriophage.'' The famous ``blender experiment'' suggests that DNA is the genetic material. When bacteria are infected by a virus, at least 80% of the viral DNA enters the cell and at least 80% of the viral protein remains outside.
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1952
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James T. Park and Jack L. Strominger demonstrate that penicillin blocks the synthesis of the peptidoglycan of bacteria. This represents the first demonstration of the action of a natural antibiotic.
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1952
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Joshua Lederberg and Norton Zinder report the discovery of a phenomenon they call ``transduction.'' Lederberg and Zinder prove that transduction in Salmonella is caused by phage particles that occasionally carry assorted host genes into new hosts (i.e., bacteriophage particles serve as the vectors of genetic exchange). The discovery of transduction is announced at Cold Spring Harbor in 1951. The next year, Zinder and Lederberg publish their results in a paper entitled ``Genetic Exchange in Salmonella. New mechanism for the heritable transfer of genetic traits from one bacterial strain to another.''
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1952
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Joshua Lederberg coins the term ``plasmid'' to describe genetic material that is capable of replicating but is not part of the chromosome.
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1952
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Karl Maramorosch demonstrates that some viruses can multiply in both plants and insects. This work leads to new questions about the origins of viruses.
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1952
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Lederberg and Ester Lederberg develop the replica plating method that allows for the rapid screening of large numbers of genetic markers. They use the technique to demonstrate that resistance to antibacterial agents such as antibiotics and viruses is not induced by the presence of the antibacterial agent.
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1952
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Renato Dulbecco develops a practical method for studying animal viruses in cell cultures. His socalled plaque method is comparable to that used in studies of bacterial viruses, and the method proves to be important in genetic studies of viruses. These methods are described in his paper ``Production of Plaques in Monolayer Tissue Cultures by Single Particles of an Animal Virus.''
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1952
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William Hayes isolates a strain of E. coli that produces recombinants thousands of times more frequently than previously observed. The new strain of K12 is named Hfr (high-frequency recombination) Hayes.
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1953
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James D. Watson and Francis H. C. Crick publish two landmark papers in the journal Nature, ``Molecular structure of nucleic acids: a structure for deoxyribose nucleic acid'' and ``Genetical implications of the structure of deoxyribonucleic acid.'' Watson and Crick propose a double helical model for DNA and call attention to the genetic implications of their model. Their model is based, in part, on the x-ray crystallographic work of Rosalind Franklin and the biochemical work of Erwin Chargaff. Their model explains how the genetic material is transmitted.
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1953
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Jonas Salk begins testing a polio vaccine comprised of a mixture of killed viruses.
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1954
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Seymour Benzer deduces the fine structure of the rII region of the bacteriophage T4 of Escherichia coli, and coins the terms cistron, recon, and muton.
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1955
|
François Jacob and Elie L. Wollman determine the mechanism of the transmission of genetic information during bacterial mating. Jacob and Wollman use a blender to interrupt the mating process and then determine the sequence of genetic transfer between bacterial cells.
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1955
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Fred L. Schaffer and Carlton E. Schwerdt report on their successful crystallization of the polio virus. Their achievement is the first successful crystallization of an animal virus.
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1955
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Heinz Fraenkel-Conrat and Robley C. Williams prove that tobacco mosaic virus can be reconstituted from its nucleic acid and protein subunits. The reconstituted particles exhibit normal morphology and infectivity.
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1956
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Alfred Gierer and Gerhard Schramm demonstrate that naked RNA from tobacco mosaic virus is infectious. Subsequently, infectious RNA preparations are obtained for certain animal viruses.
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1956
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Arthur Kornberg demonstrates the existence of DNA polymerase in Escherichia coli.
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1956
|
Joe Hin Tijo and Albert Levan prove that the number of chromosomes in a human cell is 46, not 48, as had been argued since the early 1920s.
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1957
|
Alick Isaacs and Jean Lindenmann discover and publish their pioneering report on interferon, a protein produced by interaction between a virus and an infected cell that can interfere with the multiplication of viruses.
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1957
|
François Jacob and Elie L. Wollman demonstrate that the single linkage group of Escherichia coli is circular; they suggest that the different linkage groups found in different Hfr strains are the results of different insertion points of a factor in the circular linkage group, which determines the rupture of the circle.
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1957
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Francis Crick proposes that during protein formation each amino acid is carried to the template by an adapter molecule containing nucleotides and that the adapter is the part that actually fits on the RNA template. Later research demonstrates the existence of transfer RNA.
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1957
|
The World Health Organization advances the oral polio vaccine developed by Albert Sabin as a safer alternative to the Salk vaccine.
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1958
|
Frederick Sanger is awarded the Nobel Prize in chemistry for his work on the structure of proteins, especially for determining the primary sequence of insulin.
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1958
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George W. Beadle, Edward L. Tatum, and Joshua Lederberg are awarded the Nobel Prize in Medicine or Physiology. Beadle and Tatum are honored for their work in Neurospora that led to the one gene–one enzyme theory. Lederberg is honored for discoveries concerning genetic recombination and the organization of the genetic material of bacteria.
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1958
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Matthew Meselson and Frank W. Stahl publish their landmark paper ``The replication of DNA in Escherichia coli,'' which demonstrates that the replication of DNA follows the semiconservative model.
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1959
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Arthur Kornberg and Severo Ochoa are awarded the Nobel Prize in Medicine or Physiology for their discovery of enzymes that produce artificial DNA and RNA.
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1959
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Robert L. Sinsheimer reports that bacteriophage ØX174, which infects Escherichia coli, contains a single-stranded DNA molecule, rather than the expected double stranded DNA. This provides the first example of a single-stranded DNA genome.
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1959
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Sydney Brenner and Robert W. Horne publish a paper entitled The two researchers develop a method for studying the architecture of viruses at the molecular level using the electron microscope.
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1959
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English biochemist Rodney Porter begins studies that lead to the discovery of the structure of antibodies. Porter receives the 1972 Nobel Prize in Physiology or Medicine for this research.
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1961
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François Jacob and Jacques Monod publish Genetic regulatory mechanisms in the synthesis of proteins, a paper that describes the role of messenger RNA and proposes the operon theory as the mechanism of genetic control of protein synthesis.
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1961
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Francis Crick, Sydney Brenner, and others propose that a molecule called transfer RNA uses a three-base code in the manufacture of proteins.
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1961
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Marshall Warren Nirenberg synthesizes a polypeptide using an artificial messenger RNA (a synthetic RNA containing only the base uracil) in a cell-free protein-synthesizing system. The resulting polypeptide contains only the amino acid phenylalanine, indicating that UUU was the codon for phenylalanine. This important step in deciphering the genetic code is described in the landmark paper by Nirenberg and J. Heinrich Matthaei, ``The Dependence of Cell-Free Synthesis in E. coli upon Naturally Occurring or Synthetic Polyribonucleotides.'' This work establishes the messenger concept and a system that could be used to work out the relationship between the sequence of nucleotides in the genetic material and amino acids in the gene product.
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1961
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French pathologist Jacques Miller discovers the role of the thymus in cellular immunity.
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1961
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Noel Warner establishes the physiological distinction between the cellular and humoral immune responses.
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1962
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James D. Watson, Francis Crick, and Maurice Wilkins are awarded the Nobel Prize in Medicine or Physiology for their work in elucidating the structure of DNA.
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1963
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Ruth Sager discovers DNA in chloroplasts. Boris Ephrussi discovers DNA in mitochondria.
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1964
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Barbara Bain publishes a classic account of her work on the mixed leukocyte culture (MLC) system that is critical in determining donor-recipient matches for organ or bone marrow transplantation. Bain shows that the MLC phenomenon is caused by complex genetic differences between individuals.
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1965
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François Jacob, André Lwoff, and Jacques Monod are awarded the Nobel Prize in Medicine or Physiology for their discoveries concerning genetic control of enzymes and virus synthesis.
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1966
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Bruce Ames develops a test to screen for compounds that cause mutations, including those that are cancer causing. The so-called Ames test utilizes the bacterium Salmonella typhimurium.
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1966
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Marshall Nirenberg and Har Gobind Khorana lead teams that decipher the genetic code. All of the 64 possible triplet combinations of the four bases (the codons) and their associated amino acids are determined and described.
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1967
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Charles T. Caskey, Richard E. Marshall, and Marshall Warren Nirenberg suggest that there is a universal genetic code shared by all life forms.
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1967
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Charles Yanofsky demonstrates that the sequence of codons in a gene determines the sequence of amino acids in a protein.
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1967
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Thomas Brock discovers the heat-loving bacterium Thermus aquaticus from a hot spring in Yellowstone National Park. The bacterium yields the enzyme that becomes the basis of the DNA polymerase reaction.
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1968
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Lynne Margulis proposes that mitochondria and chloroplasts in eukaryotic cells originated from bacterial symbiosis.
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1968
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Mark Steven Ptashne and Walter Gilbert independently identify the bacteriophage genes that are the repressors of the lac operon.
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1968
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Werner Arber discovers that bacteria defend themselves against viruses by producing DNA-cutting enzymes. These enzymes quickly become important tools for molecular biologists.
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1969
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Julius Adler discovers protein receptors in bacteria that function in the detection of chemical attractants and repellents. The so-called chemoreceptors are critical for the directed movement of bacteria that comes to be known as chemotaxis.
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1969
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Max Delbrück, Alfred D. Hershey, and Salvador E. Luria are awarded the Nobel Prize in Medicine or Physiology for their discoveries concerning the replication mechanism and the genetic structure of viruses.
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1969
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Stanford Moore and William H. Stein determine the sequence of the 124-amino-acid chain of the enzyme ribonuclease.
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1970
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Hamilton Smith and Kent Wilcox isolate the first restriction enzyme, HindII, an enzyme that cuts DNA molecules at specific recognition sites.
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1970
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Har Gobind Khorana announce the synthesis of the first wholly artificial gene. Khorana and his coworkers synthesize the gene that codes for alanine transfer RNA in yeast.
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1970
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Howard Martin Temin and David Baltimore independently discover reverse transcriptase in viruses. Reverse transcriptase is an enzyme that catalyzes the transcription of RNA into DNA.
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1971
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Christian B. Anfinsen, Stanford Moore, and William H. Stein are awarded the Nobel Prize in chemistry. Anfinsen is cited for his work on ribonuclease, especially concerning the connection between the amino acid sequence and the biologically active conformation. Moore and Stein are cited for their contribution to the understanding of the connection between chemical structure and catalytic activity of the active center of the ribonuclease molecule.
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1972
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Paul Berg and Herbert Boyer produce the first recombinant DNA molecules.
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1972
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Recombinant technology emerges as one of the most powerful techniques of molecular biology. Scientists are able to splice together pieces of DNA to form recombinant genes. As the potential uses—therapeutic and industrial—became increasingly clear, scientists and venture capitalists establish biotechnology companies.
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1973
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Annie Chang and Stanley Cohen show that a recombinant DNA molecule can be maintained and replicated in Escherichia coli.
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1973
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Concerns about the possible hazards posed by recombinant DNA technologies, especially work with tumor viruses, leads to the establishment of a meeting at Asilomar, California. The proceedings of this meeting are subsequently published by the Cold Spring Harbor Laboratory as a book entitled Biohazards in Biological Research.
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1973
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Herbert Wayne Boyer and Stanley H. Cohen create recombinant genes by cutting DNA molecules with restriction enzymes. These experiments mark the beginning of genetic engineering.
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1973
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Joseph Sambrook and coworkers refine DNA electrophoresis by using agarose gel and staining with ethidium bromide.
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1974
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Peter Doherty and Rolf Zinkernagel discover the basis of immune determination of self and non-self.
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1975
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César Milstein and George Kohler create monoclonal antibodies.
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1975
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David Baltimore, Renato Dulbecco, and Howard Temin share the Nobel Prize in Medicine or Physiology for their discoveries concerning the interaction between tumor viruses and the genetic material of the cell and the discovery of reverse transcriptase.
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1976
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First outbreak of Ebola virus observed in Zaire. There are more than 300 cases and a 90% death rate.
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1976
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Michael J. Bishop, Harold Elliot Varmus, and coworkers obtain definitive evidence that confirms the oncogene hypothesis. They discover that normal genes can malfunction and cause cells to become cancerous.
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1977
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Carl R. Woese and George E. Fox publish an account of the discovery of a third major branch of living beings, the Archaea. Woese suggests that an rRNA database could be used to generate phylogenetic trees.
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1977
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The last reported smallpox case is recorded. Ultimately, the World Health Organization (WHO) declares the disease eradicated.
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1977
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Frederick Sanger develops the chain termination (dideoxy) method for sequencing DNA, and uses the method to sequence the genome of a microorganism.
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1977
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Holger Jannasch demonstrates that heat-loving bacteria found at hydrothermal vents are the basis of an ecosystem that exists in the absence of light.
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1977
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Philip Allen Sharp and Richard John Roberts independently discover that the DNA making up a particular gene could be present in the genome as several separate segments. Although both Roberts and Sharp use a common cold–causing virus, called adenovirus, as their model system, researchers later find ``split genes'' in higher organisms, including humans. Sharp and Roberts are subsequently awarded the Nobel Prize in Medicine or Physiology in 1993 for the discovery of split genes.
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1980
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Paul Berg, Walter Gilbert, and Frederick Sanger share the Nobel Prize in Chemistry. Berg is honored for his fundamental studies of the biochemistry of nucleic acids, with particular regard to recombinant-DNA. Gilbert and Sanger are honored for their contributions to the sequencing of nucleic acids. This is Sanger's second Nobel Prize.
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1980
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Researchers successfully introduce a human gene, which codes for the protein interferon, into a bacterium.
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1980
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The United States Supreme Court rules that a living organism developed by General Electric (a microbe used to clean up an oil spill) can be patented.
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1981
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Karl Illmensee clones baby mice.
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1982
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The United States Food and Drug Administration approves the first genetically engineered drug, a form of human insulin produced by bacteria.
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1983
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O157:H7 is identified as a human pathogen.
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1983
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Andrew W. Murray and Jack William Szostak create the first artificial chromosome.
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1983
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Luc Montagnier and Robert Gallo discover the human immunodeficiency virus that is believed to cause acquired immunodeficiency syndrome (AIDS).
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1984
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Steen A. Willadsen successfully clones a sheep.
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1984
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The United States Department of Energy (DOE), Office of Health and Environmental Research, U.S. Department of Energy (OHER, now Office of Biological and Environmental Research), and the International Commission for Protection Against Environmental Mutagens and Carcinogens (ICPEMC) cosponsor the Alta, Utah, conference highlighting the growing role of recombinant DNA technologies. OTA incorporates the proceedings of the meeting into a report acknowledging the value of deciphering the human genome.
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1985
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Alec Jeffreys develops ``genetic fingerprinting,'' a method of using DNA polymorphisms (unique sequences of DNA) to identify individuals. The method, which is subsequently used in paternity, immigration, and murder cases, is generally referred to as ``DNA fingerprinting.''
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1985
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Elizabeth Blackburn and Carol Greider discover the enzyme telomerase, an unusual RNA-containing DNA polymerase that can add to the telomeres (specialized structures found at the ends of chromosomal DNA). Telomeres appear to protect the integrity of the chromosome. Most normal somatic cells lack telomerase, but cancer cells have telomerase activity, which might explain their ability to multiply indefinitely.
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1985
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Kary Mullis, who was working at Cetus Corporation, develops the polymerase chain reaction (PCR), a new method of amplifying DNA. This technique quickly becomes one of the most powerful tools of molecular biology. Cetus patents PCR and sells the patent to Hoffman-LaRoche, Inc. in 1991.
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1985
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Japanese molecular biologist Susuma Tonegawa discovers the genes that code for immunoglobulins. He receives the 1986 Nobel Prize in Physiology or Medicine for this discovery.
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1985
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American molecular biologist and physician Leroy Hood leads a team that discovers the genes that code for the T cell receptor.
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1986
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The United States Food and Drug Administration approves the first genetically engineered human vaccine for hepatitis B.
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1987
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Maynard Olson creates and names yeast artificial chromosomes (YACs), which provided a technique to clone long segments of DNA.
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1987
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The United States Congress charters a Department of Energy advisory committee, The Health and Environmental Research Advisory Committee (HERAC), which recommends a 15–year, multidisciplinary,
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scientific, and technological undertaking to map and sequence the human genome. DOE designates multidisciplinary human genome centers. National Institute of General Medical Sciences at the National Institutes of Health (NIH NIGMS) begin funding genome projects.
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1988
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The Human Genome Organization (HUGO) is established by scientists in order to coordinate international efforts to sequence the human genome.
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1989
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Cells from one embryo are used to produce seven cloned calves.
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1989
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James D. Watson is appointed head of the National Center for Human Genome Research. The agency is created to oversee the3 billion budgeted for the American plan to map and sequence the entire human DNA by 2005.
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1989
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Sidney Altman and Thomas R. Cech are awarded the Nobel Prize in chemistry for their discovery of ribozymes (RNA molecules with catalytic activity). Cech proves that RNA could function as a biocatalyst as well as an information carrier.
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1990
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Michael R. Blaese and French W. Anderson conduct the first gene replacement therapy experiment on a four-year-old girl with adenosine deaminase (ADA) deficiency, an immune-system disorder. T cells from the patient are isolated and exposed to retroviruses containing an RNA copy of a normal ADA gene. The treated cells are returned to her body where they help restore some degree of function to her immune system.
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1990
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Research and development begins for the efficient production of more stable, large-insert bacterial artificial chromosomes (BACs).
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1991
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The Genome Database, a human chromosome mapping data repository, is established.
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1992
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Craig Venter establishes The Institute for Genomic Research (TIGR) in Rockville, Maryland. TIGR later sequences the genome of Haemophilus influenzae and many other bacterial genomes.
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1992
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Francis Collins replaces James Watson as head of the National Center for Human Genome Research at the National Institutes of Health. Watson had clashed with Craig Venter, then at NIH, over the patenting of DNA fragments known as ``expressed sequence tags.''
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1992
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Guidelines for data release and resource sharing related to the Human Genome Project are announced by the United States Department of Energy and National Institutes of Health.
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1993
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Hanta virus emerged in the United States in a 1993 outbreak on a ``Four Corners'' area (the juncture of Utah, Colorado, New Mexico, Arizona) Native American reservation. The resulting Hanta pulmonary syndrome (HPS) had a 43% mortality rate.
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1993
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French Gépnéthon makes mega-YACs available to the genome community.
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1993
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George Washington University researchers clone human embryos and nurture them in a Petri dish for several days. The project provokes protests from many ethicists, politicians, and other critics of genetic engineering.
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1994
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DOE announce the establishment of the Microbial Genome Project as a spin-off of the Human Genome Project.
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1994
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Geneticists determine that DNA-repair enzymes perform several vital functions, including preserving genetic information and protecting the cell from cancer.
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1994
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The 5-year goal for genetic-mapping is achieved one year ahead of schedule.
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1994
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The Human Genome Project Information Web site is made available to researchers and the public.
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1995
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Peter Funch and Reinhardt Moberg Kristensen create a new phylum, Cycliophora, for a novel invertebrate called Symbion pandora, which is found living in the mouths of Norwegian lobsters.
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1995
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Researchers at Duke University Medical Center report that they have transplanted hearts from genetically altered pigs into baboons. All three transgenic pig hearts survive at least a few hours, suggesting that xenotransplants (cross-species organ transplantation) might be possible.
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1995
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The genome of the bacterium Haemophilus influenzae is sequenced.
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1995
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The sequence of Mycoplasma genitalium is completed. Mycoplasma genitalium, regarded as the smallest known bacterium, is considered a model of the minimum number of genes needed for independent existence.
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1996
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International participants in the genome project meet in Bermuda and agree to formalize the conditions of data access. The agreement, known as the ``Bermuda Principles,'' calls for the release of sequence data into public databases within 24 hours.
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1996
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Scientists report further evidence that individuals with two mutant copies of the CC-CLR-5 gene are generally resistant to HIV infection.
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1996
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The sequence of the Methanococcus jannaschii genome provides further evidence of the existence of third major branch of life on earth.
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1996
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William R. Bishai and co-workers report that SigF, a gene in the tuberculosis bacterium, enables the bacterium to enter a dormant stage.
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1997
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Ian Wilmut of the Roslin Institute in Edinburgh, Scotland, announces the birth of a lamb called Dolly, the first mammal cloned from an adult cell (a cell in a pregnant ewe's mammary gland).
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1997
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The DNA sequence of Escherichia coli is completed.
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1997
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The National Center for Human Genome Research (NCHGR ) at the National Institutes of Health becomes the National Human Genome Research Institute (NHGRI).
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1997
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William Jacobs and Barry Bloom create a biological entity that combines the characteristics of a bacterial virus and a plasmid (a DNA structure that functions and replicates independently of the chromosomes). This entity is capable of triggering mutations in Mycobacterium tuberculosis.
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1998
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Craig Venter forms a company (later named Celera), and predicts that the company would decode the entire human genome within three years. Celera plans to use a ``whole genome shotgun'' method, which would assemble the genome without using maps. Venter says that his company would not follow the Bermuda principles concerning data release.
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1998
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DOE funds bacterial artificial chromosome and sequencing projects.
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1998
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Dolly, the first cloned sheep, gives birth to a lamb that had been conceived by a natural mating with a Welsh Mountain ram. Researches said the birth of Bonnie proved that Dolly was a fully normal and healthy animal.
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1998
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Immunologist Ellen Heber-Katz, researcher at the Wistar Institute in Philadelphia, reports than a strain of laboratory mice can regenerate tissue in their ears, closing holes that scientists had created for identification purposes. This discovery reopens the discussion on possible regeneration in humans.
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1998
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The genome of the Mycobacterium tuberculosis bacterium is sequenced.
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1998
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Two research teams succeed in growing embryonic stem cells.
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1999
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The public genome project responds to Craig Venter's challenge with plans to produce a draft genome sequence by 2000. Most of the sequencing is done in five centers, known as the ``G5'': the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts; the Sanger Centre near Cambridge, United Kingdom; Baylor College of Medicine in Houston, Texas; Washington University in St. Louis, Missouri; the DOE's Joint Genome Institute (JGI) in Walnut Creek, California.
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2000
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On June 26, 2000, leaders of the public genome project and Celera announce the completion of a working draft of the entire human genome sequence. Ari Patrinos of the DOE helps mediate disputes between the two groups so that a fairly amicable joint announcement could be presented at the White House in Washington, DC.
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2001
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The complete draft sequence of the human genome is published. The public sequence data is published in the British journal Nature and the Celera sequence is published in the American journal Science.
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2001
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United States President George Bush announces the United States will allow and support limited forms of stem cell growth and research.
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2001
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In the aftermath of the September 11 terrorist attacks on the United States, a number of deaths result from the deliberate release of the bacterial agent of anthrax.
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2001
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Advanced Cell Technology announces that its researchers have created cloned human embryos that grew to the six-cell stage.
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2002
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In the aftermath of the September 11, 2001 terrorist attacks on the United States, the United States Government dramatically increases funding to programs concerned with research on microorganisms and other agents that could potentially be used in bioterrorist attacks.
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2002
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Traces of biological and chemical weapon agents are found in Uzbekistan on a military base used by U.S. troops fighting in Afghanistan. Early analysis dates and attributes the source of the contamination to former Soviet Union biological and chemical weapons programs that utilized the base.
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2002
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The planned destruction of stocks of smallpox causing Variola virus at the two remaining depositories in the US and Russia is delayed over fears that large scale production of vaccine might be needed in the event of a bioterrorist action.
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