The sparrow with four sexes (Nature)

[eppur_se_muova]

Elaina Tuttle spent her life trying to understand the bizarre chromosome evolution of a common bird — until tragedy struck.

Carrie Arnold

23 November 2016

There was one sound that biologist Rusty Gonser always heard at Cranberry Lake — and there was one sound that he would never hear again.

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 paper1 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.
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more: http://www.nature.com/news/the-sparrow-with-four-sexes-1.21018




Interesting reading -- further down is a link to an article about a protozoan with seven sexes.

[pansypoo53219]

1. OOH. we get zebra birds migrating thru. missed them this year. i call them zebra birds, we get a

similar sparrow.