We have compiled the biography of geneticist Nettie Stevens, who had a successful education life but faced a society that was against women's work in her lifetime, and despite this, her name went down in history for her studies and contributions to science.
Her full name is Nettie Maria Stevens, she was born on July 7, 1861, in Cavendish, Vermont. She was born to her mother, Julia Adams, and father, a carpenter, Ephraim Stevens. After her mother's death, her father remarried and Stevens moved with her family to Westford, Massachusetts. Nettie has a sister named Emma, and her father worked, earning enough money to provide both of them with a decent education throughout high school.
Top of her class during her education at Westford Academy, Stevens, along with her sister Emma, were two of three women to graduate from the school between 1872 and 1883. After graduating in 1880, Stevens moved to New Hampshire, Lebanon, where she learned high school zoology, physiology, mathematics, English, and Latin. Returning to Vermont three years later to continue her education, Stevens attended Westfield Normal School (now Westfield State University). She completed her four-year education in two years and managed to graduate with the highest grades in her class.
Wanting to pursue additional training in science, Stevens attended Stanford University in 1896, where she earned her undergraduate degree. She continued her education in 1899 and in 1900 with a master's degree in biology. She completed a one-year master's degree in physiology under histologist Oliver Peebles Jenkins and malacologist Frank Mace MacFarland, focusing more and more on histology.
After studying physiology and histology at Stanford, Stevens attended Bryn Mawr College to pursue her doctorate in cytology. In her doctoral studies, she made many different topics such as regeneration in primitive multicellular organisms, structure of single-celled organisms, development of sperm and eggs, reproductive cells of insects, cell division in sea urchins and worms. At the same time, she expanded the fields of genetics, cytology, and embryology.
During her graduate studies, Stevens, who was elected President's European Fellow, spent a year (1901-02) at the Zoological Station in Naples, where she worked with marine organisms. She also took a position at the Institute of Zoology at the University of Würzburg.
Stevens, who received her doctorage degree from Bryn Mawr in 1903, spent a year as a research assistant in biology. She continued as a reader in experimental morphology for another year at the university, where she served as an assistant in the field of experimental morphology from 1905 until her death. Her long-desired position as research professor at Bryn Mawr College was offered just before she died of cancer, and Stevens turned it down because of her ill health.
Awarded as a research fellow at the Carnegie Institution of Washington in 1904-1905, Stevens' years of work there required fellowship support. Applying for funding to research on Mendelian laws of heredity, particularly sex determination, Stevens, after receiving the grant, considered using aphid germ cells to examine possible differences in chromosome sets between the two sexes. The major sex determination work was published by the Carnegie Institution in the two-part monograph "Studies in Spermatogenesis," which highlights the issue of sex determination studies and chromosomal inheritance.
In 1908, Stevens was awarded the Alice Freeman Palmer Fellowship from the Collegiate Alumnae Association. Also, one of the first American women to be recognized for her contributions to science, Stevens completed most of her research at Bryn Mawr. Despite not having a university education, Stevens built a career for herself doing research at marine stations and laboratories.
Stevens, who recorded 38 publications, included several important contributions that developed the chromosomal inheritance concepts that emerged in them. Stevens, who also conducted experiments on germ cells, realized from her data that chromosomes play a role in determining sex during development.
Using observations of insect chromosomes, Stevens noticed that in some species the chromosomes differ between the sexes. She also discovered that when chromosomal segregation occurs in sperm formation, this difference leads to consequences for male and female offspring. Her discovery was the first to discover that observable chromosome differences could be associated with phenotype or physical traits. This work was published in 1905, and she used a number of insects in her ongoing experiments.
She found a small chromosome known as the Y chromosome in Tenebrio, now known as the flour worm she. Thus, she understood that the chromosomal basis of sex was due to the smaller Y chromosome carried by the male, she. Stevens explained that "an egg fertilized by a sperm with a smaller chromosome will be a male; an egg fertilized by a sperm with a larger chromosome will be a female." In addition, by examining the egg tissue and fertilization process of many living things, Stevens noticed the existence of small-large pairs (now known as XY chromosome pairs) and unpaired chromosomes (XO).
The chromosome found by Hermann Henking, now called X, was found, but the small chromosome, now called Y, was not found she. Stevens said that determining sex depends on the presence or absence of the small (Y) chromosome. Stevens, who did not name the X or Y chromosomes, took the current names later.
Although Stevens had worked on chromosomal sex determination, she was not mentioned by many authors. Additionally, the discovery earned another geneticist a Nobel Prize. Stevens was also not invited to any conference on the theories put forward on this subject.
Stevens, 50, died of breast cancer on May 4, 1912, in Baltimore, Maryland. Stevens, whose career span was short, has published about 40 articles. Stevens also never married and had no children.
After Stevens' death, some geneticists said that Stevens "had a share in an important discovery." In 1994, Stevens was inducted into the National Women's Hall of Fame. On July 7, 2016, Google created a doodle showing Stevens looking through a microscope at XY chromosomes to celebrate her birthday. On May 5, 2017, Westfield State University named the chapter "Dr.Nettie Maria Stevens Center for Science and Innovation" named after Stevens and honored Stevens at the naming ceremony.
It was thought that Stevens, who was one of the first women whose value was partially understood because of what she presented to the world of science, would have contributed more to science and the earth if her scientific activities had started at an earlier age.