Hermann Henking

{{short description|German biologist who discovered the X chromosome}}

Hermann Paul August Otto Henking (16 June 1858 – 28 April 1942)James Wynbrandt, Mark D. Ludman, The Encyclopedia of Genetic Disorders and Birth Defects, page 395, Infobase Publishing, 2009 {{ISBN|1438120958}}. was a German cytologist who discovered the X chromosome in 1890 or 1891. The work was the result of a study in Leipzig of the testicles of the firebug (Pyrrhocoris apterus), during which Henking noticed that one chromosome did not take part in meiosis. He named this the X element because its strange behaviour made him unsure whether it was genuinely a chromosome.James Schwartz, In Pursuit of the Gene: From Darwin to DNA, pages 155–158, Harvard University Press, 2009 {{ISBN|0674034910}} It was later named the X chromosome after American cytologist Clarence Erwin McClung established that it was not only a genuine chromosome but a sex-determining one, though McClung incorrectly guessed that it was the male-determining sex chromosome.David Bainbridge, The X in Sex: How the X Chromosome Controls Our Lives, pages 3–5, Harvard University Press, 2003 {{ISBN|0674016211}}.