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Re: Study: Platypus Retains Bird Sex Link



You're laughing, right?

Seriously, I've already seen the first article.   It says that while
platypuses have ten sex chromosomes, one of the x chromosomes is similar to
a bird sex chromosome.

I thought that all reptiles had the basic sex chromosome structure of birds.
It is backwards from taht of mammals; the letters are different, for
different chromosomes, I guess; but with birds, two of a particular
chromosome makes one a male, and one of each makes one a female.

I understand that mammals are descended from a very primitive reptile near
the foot of the reptile family tree.    Dinosaurs are very highly evolved
reptiles near the top fo the reptile family tree.   Birds belong to one of
the major branches of dinosaurs, and they are highly evolved relative to
their feathered cousins.

So if tehre are similarities between a promitive mammal, probably LONG
removed from its common ancestor with other mammals, and birds, then
wouldn't the reason why be that reptiles were our ancestors?

Yours,
Dora Smith
Austin, Texas
The American Colonies
villandra@austin.rr.com
----- Original Message -----
From: "Jacquie" <jacquieh49@yahoo.com>
To: <dinosaur@usc.edu>
Sent: Tuesday, October 26, 2004 8:26 AM
Subject: Study: Platypus Retains Bird Sex Link


>
> http://animal.discovery.com/news/briefs/20041025/platypus.html
>
> http://dsc.discovery.com/news/briefs/20041025/platypus.html
> Does this mean mammals are dinosaurs, too? :o)
>
>
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