Re: New extinction theory

[Aidan Karley <aidan_karley@yahoo.co.uk>]

In article <000f01c56a48$f3bf0960$690fa8c0@austin.rr.com>, Dora Smith 
wrote:
> Offhand, from what was attached here, it looks like he's saying dinosaurs
> possibly went extinct because they were molecularly different from other
> reptiles.
>
       I don't have access to the paper under discussion, but I remember 
from elsewhere that there's a degree of correlation between the G+C 
proportion of an organism's genome and it's optimal temperature for growth 
(talking bacteria and other things you can grow in culture, not complex, 
difficult organisms). The explanation is that (IIRC) a higher G+C 
proportion has more charge per length of DNA, which helps bind the strands 
together in the super-coils, and that makes the strands more resistant to 
thermal damage. 
       Given that background, the molecular people's attempts to find a 
"molecular basis for extinction" seems at least vaguely sensible. Different 
details of DNA-handling physiology *could* influence survival in stressed 
conditions. <in voice of molecular biologist> Well, it works in the culture 
flask! Just don't disturb me with details like behaviour and crocodiles 
changing their brood sex ratios with brood incubation temperature. </voice>
-- 
 Aidan Karley,
 Aberdeen, Scotland,
 Location: 57°10' N,  02°09'  W (sub-tropical Aberdeen), 0.021233
 Written at Mon, 06 Jun 2005 09:57 +0100



                
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