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Re: Platypus genome



evelyn sobielski writes:


(much like humans appear to be losing theirs).

Actually that's a general trend in mammals, and human Y chromosomes are not that much reduced - _Sminthopsis_ is the crassest case known (one-fifth the mammal one's size, 4 functional genes), and they're marsupials. I don't know if there's a phylogenetic pattern in Y chromosome reduction, but the only thing that's really crucial on that thing is the SRY gene. And that can transpose - rarely, but it has happened at least once and perhaps twice in _Ellobius_ (a rodent).

Apparently there are already men who don't have a Y chromosome at all, but rather two Xs. Apparently whatever 'crucial' genes on the Y chromosome that cause an embryo to develep as male have been replaced by genes on other chromosomes in those (very rare) cases.


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Dann Pigdon
GIS / Archaeologist              http://geo_cities.com/dannsdinosaurs
Melbourne, Australia             http://heretichides.soffiles.com
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