Nettie Stevens

Nettie Stevens

Nettie Maria Stevens was born in 1861 in Cavendish,Vermont. She was an American biologist and geneticist, whose research proved that chromosomes determine the sex of an organism. She completed in only two years the four-year course at Westfield Normal School in Massachusetts. Nettie graduated with the highest academic scores in her class. She received

her B.A. in 1899 and her M.A. in 1900 at Stanford.

Nettie studied Tenebrio molitor beetles and found that unfertilized eggs in female beetles always contain an X chromosome. Sperm from male beetles contain either an X chromosome or a Y chromosome. She found that eggs fertilized by sperm carrying the X chromosome produce female beetles. The combination of egg and Y-chromosome sperm produce male beetles.

Edmund Beecher Wilson, a biologist from Columbia University in New York City, made this same discovery at about the same time as Nettie. Nettie also established that chromosomes exist as paired structures in body cells.

Nettie Stevens was not credited very well for her discovery. Instead, someone else was given the credit even though Nettie had done all of the