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Dobzhansky, Theodosius

genetics evolution natural species

[dob zhan skee] (1900–75) Russian–US geneticist: linked ideas of evolution with laws of genetics and so was a creator of evolutionary genetics.

He studied zoology in Kiev and later taught there and in St Petersburg before, in 1927, joining research group working on Drosophila genetics in Columbia University, New York City. Morgan, a major figure in modern genetics, moved to California in 1928, and Dobzhansky joined him the following year and spent his later career there and in New York.

Dobzhansky’s book Genetics and the Origin of Species (1937) brought together the ideas of field naturalists and geneticists, both experimental and mathematical, to create a single argument on the process of evolution. His work with Drosophila had made him very aware that natural mutations can lead to large or small apparent changes, that these are acted upon by natural selection and that genes may interact and so give rise to variation which appears continuous rather than stepwise. He showed that natural selection could be seen in action, for example in the spread of scale insects resistant to control by cyanide gas, used as an insecticide in Californian citrus groves.

Dobzhansky developed good arguments for his view that a new species cannot arise from a single mutation and that, for a new species to form, it must for a period be isolated to protect it from disruption. The isolation could be geographical or due to differences in habitat or in the breeding season.

His work on human evolution led him to define races as ‘Mendelian populations which differ in gene frequencies’, as outlined in his Genetics of the Evolutionary Process (1970).

Doc Martens (R. Griggs Co.) [next] [back] Dobie, Edith (1887–1975) - British History

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