Originally shared by Kam-Yung Soh
A fascinating look at what might be the development of a new sex gene in this bird paired with a profile of the scientists but includes a tragedy: just months after publishing their last paper together, she passes away from cancer. “Every summer for more than 25 years, Gonser and his wife, Elaina Tuttle, had made the trip to this field station in the Adirondack Mountains — a 45-minute boat ride from the nearest road. Now, as he moored his boat to the shaky wooden dock, he heard a familiar and short song that sounded like ‘oh-sweet-Canada’. The whistle was from a white-throated sparrow calling hopefully for a mate.
What he didn’t hear was the voice or laughter of his wife. For the first time, Gonser was at Cranberry Lake alone. Just a few weeks earlier, Tuttle had died of breast cancer.
Her entire career, and most of Gonser’s, had been devoted to understanding every aspect of the biology of the white-throated sparrow (Zonotrichia albicollis). Less than six months before she died this year at the age of 52, the couple and their team published a paper that was the culmination of that work. It explained how a chance genetic mutation had put the species on an extraordinary evolutionary path.
The mutation had flipped a large section of chromosome 2, leaving it unable to pair up with a partner and exchange genetic information. The more than 1,100 genes in the inversion were inherited together as part of a massive ‘supergene’ and eventually drove the evolution of two different ‘morphs’ — subtypes of the bird that are coloured differently, behave differently and mate only with the opposite morph. Tuttle and Gonser’s leap was to show that this process is nearly identical to the early evolution of certain sex chromosomes, including the human X and Y. The researchers realized that they were effectively watching the bird evolve two sex chromosomes, on top of the two it already had.”
http://www.nature.com/news/the-sparrow-with-four-sexes-1.21018
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