Stevens, Nettie Maria

Nettie Stevens has been recognised recently for her careful research postulating that the chromosomes are involved in the inheritance of a specific character, sex. The background of her achievement is discussed, including the behaviour of the chromosomes in cell division, the results of experimental breeding, and the possibility that the two are related. Through exploring her early life and education, her relationship to her colleagues who, while praising her work, did not give her the credit she deserved, and the professional difficulties that she as a woman encountered, Stevens’ importance in the history of genetics is considered. Key Concepts: Nettie M. Stevens is most noted for postulating that sex is determined by a specific chromosome. Stevens shares credit for this discovery with Edmund B. Wilson. Wilson is more often credited for this discovery both because he made more contributions to the history of biology and because Stevens was a woman. The discovery of the sex chromosome helped establish the idea that chromosomes were responsible for the inheritance of a specific characteristic, sex. Keywords: chromosomes; cytology; Walter S. Sutton; Edmund B. Wilson; cytogenetics; Thomas Hunt Morgan; Tenebrio molitor; spermatogenesis; oogenesis; heterochromosomes