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EARLY HISTORY OF EPIGENETICS From Jean-Baptiste Lamarck to Conrad Hal Waddington Boris Vyskot Department of Plant Developmental Genetics Institute of Biophysics, Czech Academy of Sciences, Brno Realistic Drama from the History of Developmental and Evolutionary Biology - in three acts (plus prologue and epilogue) - taking place in Europe from the beginning of the 19th century to the mid of the 20th century Prologue: Theory of Adaptive Evolution (Lamarck) Act One: Of Toads and Man (Kammerer) Act Two: Creative Soviet Darwinism (Lysenko) Act Three: Great Renaissance Heretic (Waddington) Epilogue: Epigenetics (to be continued) Prologue Historic overture or theory of adaptive evolution Jean-Baptiste Lamarck (1744-1829) • Theory of biological evolution Evolution (development) occurs from mineral forms to living organisms, from simple forms to complicated ones, which result in perfectly adopted organisms. • Use and disuse of organs Organisms react on changing environment by development of new organs or by changing the structure and function of current organs. • Inheritance of acquired traits Traits acquired during the life of organism are transmitted into sexual progeny (discredited by Weismann). Lamarck coined the term biology and invertebrates, and invented the first evolutionary „soft“ theory. His theories of adaption form a philosophical basis of modern epigenetics Lamarck had a different opinion on evolution compared with Darwin. He believed that simple forms of life continuously pass to more complicated ones to become perfect, and are transformed into new species. Lamarck’s reputation suffered when problematic experiments were made by other researchers who wanted to disclaim or support his ingenious ideas Act One How One Toad Destroyed One Man’s Career Starring baddie: Dr. Paul Kammerer (Vivarium Vienna, researcher, pianist, and lover) advocates: Prof. Hans Przibram (Vivarium, director) Prof. E.W. MacBride (zoologist) prosecutors: G.K. Noble (keeper of reptiles, Alytes) H.M. Fox (zoologist, Ciona) J.R. Whitaker (marine biologist, Ciona) critics: Prof. R. Goldschmidt (geneticist, Proteus) Prof. William Bateson (geneticist) epilogue: Lunacarskij: Salamandra, Russian film (1927) A. Koestler: The Case of the Midwife Toad, book (1971) The plot occurs in Vienna and runs on pages of the famous journal Nature at the beginning of the 20th century Paul Kammerer (1880-1926) and environmental vitalism Sequence ONE (Kammerer 1909) SALAMANDRA reproductive adaptation of two species of salamander Salamandra maculosa (mottled, lowland) Salamandra atra (black, alpine) Change of environmental conditions (temperature, humidity) leads to a modification of their reproductive behaviour, the inheritance was not checked. Sequence TWO (Kammerer 1912) NEWT environmental (experimental) manipulation of ontogenesis Proteus anguinus, the blind cave newt Exposure to red light does not cause pigmentation of the skin and, thus, permits development of completely functional eyes. Inheritance of this developmental change was not followed. Sequence THREE (Kammerer 1923) CIONA experimental induction of a new trait and its inheritance Ciona intestinalis, sea squirt (ascidian, Urochordata) Amputation of siphon ends (stoma and anus) leads to regeneration of prolonged siphons and this trait is inherited by successive generations even without any other amputation (“hyper-regeneration“). Fox (1923) and Whitaker (1975) did not confirm these results. Sequence FOUR (Kammerer 1923) TOAD environmental induction of a new trait and its inheritance Alytes obstetricans, midwife toad Incubation of toads in water environment invokes formation of „nuptial pads“ on forelimbs of males, this trait is transmitted by sexual progeny even without the inducing environment. Noble (1926) documented injection of Indiand ink in the Kammerer’s specimen. Summary Kammerer, P.: Breeding experiments on the inheritance of acquired characters. Nature 113: 637, 1923 Fox, H.M.: Dr. Kammerer’s Ciona experiments. Nature 112: 653, 1923 Kammerer, P.: The Inheritance of Acquired Characters. Boni & Liverlight, USA 1924 Noble, G.K.: Kammerer‘s Alytes. Nature 118: 209, 1926 … KAMMERER COMMITED SUICIDE .... 1926 Przibram, H.: Nature, 1926 (obituary) Koestler, A.: The Case of the Midwife Toad. London 1971 Whitaker, J.R.: The case of the suspicious siphons Ciona revisited. Science News 107: 348, 1975 Act Two The Drama Continues or „the Creative Soviet Darwinism“ Plot occurs in the Soviet Union and other communist countries at the 30’s to 50’s of the 2Oth century Trofim Denisovic Lysenko (1898-1976) Lysenko, Trofim Denisovic Russian agronomist, father of „transmutations“ - as the President of The Lenin Academy of Agricultural Sciences he has become the scientific and administrative leader of Soviet biology in 40th to 50th of the XX century - using a traditional process of vernalization (moistening and cooling of seeds) he reputedly changed properties of the spring wheat to the winter wheat) - a part of the communist ideology exagerrating the influence of environment on living organisms, rejecting genetics - based on the work of the old orchardist Mitschurin, in plant and animal breeding he continued such ideas as vegetative hybridization Principles of „the Creative Soviet Darwinism“ - the basis of co-ordination of organisms and environment is metabolism (exchange of substances) - disturbance of metabolism results in loss of ability of selection and creation of changes (mutations?) - inheritance is the result of concentration of various environmental factors assimilated by organisms in many preceding generations - evolution cannot proceed without inheritance of changes, which have been acquired by the organism during its life - inheritance in plants and animals can be controlled (only) by environmental factors Nikolai I. Vavilov (St. Peterburgh: 1887-1943) Geneticist and breeder, the father of Russian genetics Prisoner Nikolai I. Vavilov (Saratov, 1943) Act Three Life and Ideas of the Great Renaissance Heretic Conrad Hal Waddington Genetic assimilation in vitro Conrad Hal Waddington (1953) Phenocopy of mutation bithorax Selection experiments on the„bithorax“ (the second pair of wings) reaction after aplication of ether on embryos Other important roles of environment unfolding of hidden genetic variation standard “without cross-veins“ generation P F1 F14 % „without cross-veins“ (heat shock) 23 79 97 % „without cross-veins“ (no heat shock) 0 0 1-2 - the trait, once environmentally switched on, becomes assimilated in the genome Interpretation of genetic assimilation canalization (co-ordination) = suppression of phenotypic variation, assuring of “normal development”, roles of heat-shock proteins as a buffer of “developmental protein factors”, restricted motion in epigenetic landscape critical points differently sensitive to environmental changes wild-type alternative phenotypes Epilogue Inheritance is more complicated than we (Mendel, Watson, Crick …) thought. Recent progress in epigenetics favours the ghost of Lamarck. Renaissance of heresy?
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