FROM

science

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How did the chicken lose its penis? By killing off the growing appendage in the egg.

That’s the finding of a new study, which reveals how most birds evolved to lose their external genitalia. Turns out, a particular protein released during the development of chickens, quail and most other birds nips penis development in the bud, according to the new research, published today (June 6) in the journal Current Biology.

The findings have implications for genital development in general, which is important because birth defects in the external genitalia are among the most common congenital defects in humans, said study researcher Martin Cohn, a developmental biologist at the Howard Hughes Medical Institute and the University of Florida.

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Birds Penises

The chicken embryo develops the beginnings of a penis, but the growth of the organ halts and regresses before hatching.

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.Click link below for story and slideshow:

http://www.huffingtonpost.com/2013/06/06/birds-penises-protein-genitals_n_3397504.html?ref=topbar

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