Johannsen, Wilhelm Ludvig

Johannsen, Wilhelm Ludvig

(born Feb. 3, 1857, Copenhagen, Den.—died Nov. 11, 1927, Copenhagen) Danish botanist and geneticist. He supported Hugo de Vries's discovery that variation in genotype can occur by mutation; the new character, while independent of natural selection in its initial occurrence, is then subject to natural selection. Johannsen's Elements of Heredity (1909) became an influential text, and his terms phenotype and genotype are now a part of the language of genetics.