telomeres

Kurt Schaudt olxsc01 at mailserv.zdv.uni-tuebingen.de
Thu Jun 2 15:45:34 EST 1994



On 28 May 1994, ABUBU wrote:

> In article <68388 at sdcc12.ucsd.edu>, wsun at jeeves.ucsd.edu (Fiberman)
> writes:
> 
> >There's no selection for longevity genes since as long as
> >an organsim reaches the reproductive age, it has survived well
> >in the evolutionary sense. 
> 
> I have heard this several times, but I do not see why.  Wouldn't an
> organism that stayed as a reproductive adult permanently have a great
> advantage?  It could have ten times (just to pick a number) as many
> offspring as another organism that aged normally.  It would also have
> a better chance of staying alive, and rearing it's young by virtue of
> experience.

I am not persuaded by this argument. If the longevity genes of the 
organism would be not dominant it would not render his longevity to its 
offspring - except it would meet a partner with the same longevity genes.
 
I think that this is extremely unlikely because such genomic longevity 
structure must be very complex and would affect multiple genes. 

I don't think that there are any genomic programs responsible for 
promoting ageing (telomere shortening seems not to affect our real 
lifespans) but there must be programs for counteracting 
ageing processes (accumulated poisoning, damages by oxidants and so on).

As long as ageing processes are hindering the organism from reproduction 
there is a most strong evolutionary pressure for developing and 
enhancing genomic programs that counteract ageing. When lifespan is 
sufficient to have enough offspring this pressure vanishes totally.




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