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From: sarima@tdatirv.UUCP (Stanley Friesen)
Newsgroups: sci.bio
Subject: Re: baby dodo
Message-ID: <65@tdatirv.UUCP>
Date: 19 Nov 90 20:12:49 GMT
References: <1990Nov14.005513.28666@massey.ac.nz>
Reply-To: sarima@tdatirv.UUCP (Stanley Friesen)
Organization: Teradata Corp., Irvine
Lines: 30

In article <1990Nov14.005513.28666@massey.ac.nz> A.S.Chamove@massey.ac.nz (A.S. Chamove) writes:
>My question is why is it not possible to recreate extinct animals?

Mostly because a 100% intact genome is necessary.

>In the simplest situation, when samples of moist tissue remain 
>(as is the case with the Mastodon where frozen bits have been found
>in the far North), why cannot the DNA be removed from a cell and 
>implanted into an ovum and carried by a related creature (elephant
>in this case)?

Because DNA is a rather 'unstable' long-chain polymer that begins to break
down shortly after death.  Thus even the 'quick' freeze that preserved the
Mammoths &c. has allowed the DNA to degrade too far for full reconstruction.
[The meat is actually rather rotten in these frozen carcasses, far too
decayed for intact DNA.  I suppose with a giant cmputer, and lots of patience,
you could reconstruct the intact DNA from the bits and pieces in the millions
of cells in the carcasses, but that is *lots* of work].

>In the case where only dry bits remain (the bones of Australopithecus or
>the dry skin of the Dodo or Moa or Passenger Pigeon),  are there
>active or recoverable strands of DNA which could be comparably
>removed and implanted into a living ovum?

Probably not, these hard tissues are mostly non-cellular even in *living*
organisms, so they never had much DNA to start with.  (The skin of the Dodo
might include the dermis (the living layer), but I doubt it)
-- 
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uunet!tdatirv!sarima				(Stanley Friesen)