Re: FW: A Perspective on Cope's Rule

[Tim Williams <twilliams_alpha@hotmail.com>]

David Marjanovic wrote:

> On the one hand, small animals have higher metabolism and therefore more 
> mutations.

I've heard this said a few times: Small mammals have a more rapid 
metabolism, therefore they generate more free radicals, therefore there is 
more oxidative damage to the DNA, therefore the DNA accumulates more 
mutations.  However, the genomic DNA is contained within the nucleus, and is 
endowed with its own suite of DNA-repair enzymes.  So, I'm not at all sure 
that higher metabolism = higher mutation rate is actually true (apart from 
mitochondrial DNA, perhaps).  Do you have references?

Also, the small animals = higher metabolism thing really only holds for 
endotherms.