J. B. S. Haldane

John Burdon Sanderson Haldane (1892 to 1964) was a British-Indian geneticist and physiologist who, with Ronald Fisher and Sewall Wright, founded the mathematical theory of population genetics. He was known for his wit as much as for his science.

In a series of papers beginning in 1924 and in his 1932 book The Causes of Evolution, Haldane worked out how fast a beneficial gene can spread through a population under natural selection. His calculations showed that selection could act quickly enough to explain evolution, which helped to bring Mendelian genetics and Darwin's theory together in the modern synthesis. In 1957 he raised the "cost of selection" problem, now often called Haldane's dilemma, about how many substitutions a lineage can afford.

Haldane's rule, from 1922, states that when one sex is rare, absent or sterile in hybrid offspring, it is the sex with two different sex chromosomes. In 1915 he and colleagues gave early evidence of gene linkage in vertebrates, and the Haldane mapping function converts recombination rates into map distance. He also worked on enzymes and human physiology, including diving and mining safety.

A committed Marxist for part of his life and an outspoken critic of authority, Haldane left Britain in 1957 for India, where he worked at the Indian Statistical Institute and later in Bhubaneswar. He is remembered for the line that the universe may be queerer than we can suppose, and his writings on evolution reached a wide public.