Susumu Ohno

Susumu Ohno (February 1, 1928 – January 13, 2000), was an Asian American geneticist and evolutionary biologist, and seminal researcher in the field of molecular evolution.

Biography
Susumu Ohno was born of Japanese parents in Seoul, Korea, on February 1, 1928. The second of five children, he was the son of the minister of education of the Japanese Viceroyship of Korea. The family returned to Japan after the war in 1945. Later he became a citizen of the United States of America. Susumu Ohno married Midori Aoyama in 1951. They had two sons and one daughter.

His passion for science derived from his life-long love of horses. He earned a Ph.D. in veterinary science at Tokyo University of Agriculture and Technology in 1949, and later a Ph.D. and D.Sc. from Hokkaido University. He went to the United States in 1951, as a visiting scholar to UCLA, and in 1952 joined the new research department at City of Hope Medical Center, where he remained in active research until 1996.

Scientific contributions
Ohno postulated that gene duplication plays a major role in evolution in his classic book Evolution by Gene Duplication (1970). While subsequent research has overwhelmingly confirmed the key role of gene duplication in molecular evolution, research to evaluate Ohno's model for the preservation of duplicate genes (now termed neofunctionalization) is ongoing and very active. He also discovered in 1956 that the Barr body of mammalian female nuclei was in fact a condensed X chromosome. In Evolution by Gene Duplication, he also suggested that vertebrate genome is the result of one or more entire genome duplications; variations of this idea have come to be known as the 2R hypothesis (also called "Ohno's hypothesis").