nettie stevens 155th birthday-american geneticist, confirmed chromosomal basis of sex
Nettie Stevens
Born Nettie Maria Stevens
July 7, 1861
Cavendish, Vermont, United States
Died May 4, 1912 (aged 50)
Baltimore, Maryland, United States
Fields Genetics
Education Westford Academy
Alma mater Westfield Normal School
Stanford University
Bryn Mawr College
Doctoral students Alice Middleton Boring
Known for XY sex-determination system
Influences Edmund Beecher Wilson
Thomas Hunt Morgan
Nettie Maria Stevens (July 7, 1861 – May 4, 1912) was an early American geneticist. In 1905, she and Edmund Beecher Wilson were the first researchers to independently describe the chromosomal basis of sex.[1][2]
. . . . .
In her first year at Bryn Mawr, Stevens received a graduate scholarship in biology. The following year, she was named a President's European Fellow, and studied at the University of Würzburg, Germany.[1] She also studied marine organisms at Helgoland and Naples Zoological Station.[5][6] After receiving her Ph.D. from Bryn Mawr, Stevens was given an assistantship at the Carnegie Institute of Washington in the year 1904–1905. Several subsequent studies of germ cells in aphids appeared as a result. One paper (1905) won Stevens an award of $1,000 for the best scientific paper written by a woman. Another work, "Studies in Spermatogenesis," highlighted her entry into the increasingly promising focus of sex-determination studies and chromosomal inheritance.[1] It was at this institute that Stevens had her sex determination work published as a report in 1905.[2] At Bryn Mawr, Stevens focused on topics such as the regeneration in primitive multicellular organisms, the structure of single cell organisms, the development of sperm and eggs, germ cells of insects,[1] and cell division in sea urchins and worms. In 1908, Stevens received the Alice Freeman Palmer Fellowship from the Association of Collegiate Alumnae, now the American Association of University Women. During her fellowship year, Stevens studied at the Naples Zoological Station and the University of Wurzburg in addition to visiting laboratories throughout Europe.[7]
Stevens was one of the first American women to be recognized for her contribution to science. Her research was done at Bryn Mawr College. Her highest rank attained was the associate in experimental morphology (1905–1912). She discovered that, in some species, chromosomes are different among the sexes using observations of insect chromosomes. The discovery was the first time that observable differences of chromosomes could be linked to an observable difference in physical attributes (i.e., whether an individual is male or female). This work was done in 1905. The experiments done to determine this used a range of insects. She identified the Y chromosome in the mealworm Tenebrio. She deduced that the chromosomal basis of sex depended on the presence or absence of the Y chromosome. She did not start her research until her thirties and completed her PhD in 1903. She successfully expanded the fields of genetics, cytology and embryology.[1]
Stevens failed to gain a full regular university position. However, she achieved a research career at leading marine stations and laboratories. Her record of 38 publications includes several major contributions which further the emergence of ideas of chromosomal heredity. As a result of her research, Stevens provided critical evidence for Mendelian and chromosomal theories of inheritance.[1] Stevens worked to be able to become a full researcher at Bryn Mawr. However, before she could take the research professorship offered to her, she died May 4, 1912, of breast cancer at Johns Hopkins Hospital.[6]
. . . . .
https://en.wikipedia.org/wiki/Nettie_Stevens