Codice albumGBB-F-006509

Codice inventarioGBB-F-006509-0000

1895 ca, USA: The biologist and early American geneticist Doctor NETTIE STEVENS (1861-1912). In 1906, she discovered that male beetles produce two kinds of sperm, one with a large chromosome and one with a small chromosome. When the sperm with the large chromosome fertilized eggs, they produced female offspring, and when the sperm with the small chromosome fertilized eggs, they produced male offspring. This pattern was observed in other animals, including humans, and became known as the XY sex-determination system

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