From Today in Science History:
Wilhelm Ludvig Johannsen. Born 3 Feb 1857; died 11 Nov 1927.
Danish botanist and geneticist whose experiments in plant heredity offered strong support to the mutation theory of the Dutch botanist Hugo de Vries (that changes in heredity come about through sudden, discrete changes of the heredity units in germ cells). Many geneticists thought Johannsen’s ideas dealt a severe blow to Charles Darwin’s theory that new species were produced by the slow process of natural selection. In 1909, Johannsen proposed that each portion of a chromosome that controls a phenotype be called a “gene” (Greek: “to give birth to”).
Wilhelm Johannsen Centre for Functional Genome Research
(Image from Wikimedia Commons)