Sewall Wright
(born Dec. 21, 1889, Melrose, Mass., U.S.?died March 3, 1988,
Madison
, Wis.) was an American geneticist, one of the founders of
population genetics
. He was the brother of the political scientist
Quincy Wright
.
Wright was educated at Lombard College, Galesburg, Ill., and at the
University of Illinois
, Urbana, and, after earning his doctorate in zoology at
Harvard University
(Sc.D., 1915), he worked as a senior
animal
husbandman for the
U.S. Department of Agriculture
(1915?25). He was a professor at the
University of Chicago
(1926?54) and then at the
University of Wisconsin
, Madison (1955?60). He continued to publish scientific papers after his retirement.
Britannica Quiz
Faces of Science
Wright’s earliest studies included investigation of the effects of
inbreeding
and crossbreeding among guinea pigs, animals that he later used in studying the effects of
gene
action on coat and
eye colour
, among other
inherited
characters. Along with the British scientists J.B.S. Haldane and R.A. Fisher, Wright was one of the scientists who developed a mathematical basis for modern evolutionary theory, using statistical techniques toward this end. He also originated a theory that could guide the use of inbreeding and crossbreeding in the improvement of livestock. Wright is perhaps best known for his concept of
genetic drift
, called the Sewall Wright effect, which says that when small populations of a species are isolated, out of pure chance the few individuals who carry certain relatively rare genes may fail to transmit them. The genes may therefore disappear and their loss may lead to the emergence of new species, although
natural selection
has played no part in the process.