Clarence McClung, co-discoverer of the chromosome responsible for sex determination, was born in Clayton, California, the son of civil engineer and a physician's daughter. After public high school in Columbus, Kansas, he received a degree from the University of Kansas School of Pharmacy in 1892, taught chemistry and pharmacy for a year, then enrolled in the University of Kansas as an undergraduate. As the protégé of histologist Samuel Wendell Williston (1851-1918), McClung received his B.A. in 1896, M.A. in 1898, and Ph.D. in 1902. While a graduate student at Kansas, he also studied under Edmund Beecher Wilson (1856-1939) at Columbia University and William Morton Wheeler (1865-1937) at the University of Chicago. The University of Kansas named him assistant professor of zoology in 1898, associate professor in 1901, and full professor in 1906. Among his students was Walter Stanborough Sutton (1877-1916). He also served the University of Kansas from 1902 to...