Daily Archives: 23 May 2014

May 23, 1905 (a Tuesday)

Nettie Stevens (1904)

Nettie Stevens (1904)

On this date, Nettie Maria Stevens submitted her manuscript “Studies in Spermatogenesis with Especial Reference to the ‘Accessory Chromosome'” to the Carnegie Institution for publication in the Carnegie monograph series. It was sent on May 29 to E.B. Wilson, a member of the institution’s advisory committee, for his opinion. He returned it on June 13 with the brief statement: “It is in every way a most admirable piece of work which is worthy of publication by any learned society, and I do not hesitate to recommend it to you for publication by the Institution.” Wilson’s comments were an understatement; her research paper was one of the 20th century’s major scientific breakthroughs.

Stevens’ monograph was published in September 1905, the first documentation that observable differences in chromosomes could be linked to an observable difference in physical attributes, i.e. if an individual is a male or a female. This caused many at the time to re-evaluate earlier conclusions of sex determination, and to begin looking more generally at a chromosomal basis for animal sex determination.

Nettie Stevens, educated at Stanford University and Bryn Mawr College (Ph.D., 1903), taught throughout her relatively short life, inspiring many students to careers in science. She published more than 38 papers from 1901 to her death (1912), in cytology and experimental physiology.

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May 23, 1707

Celebration of Linnaeus' 300th Birthday.

On this date, the Swedish botanist, zoologist and geologist Carolus Linnaeus was born. He presented his revolutionary sexual system of plants for the first time in 1735. His contemporaries were shocked by the frank parallels Linnaeus made to human sexuality – nevertheless his practical system was soon to spread around the world.