> An opinion I have read is that increased lifespan under CR may be a way of an
> organism making the "best of a bad lot" when conditions are so bad that it
> would be unlikely that offspring would survive. Extending life until
> conditions improved may be a strategy that has evolved that optimises
> reproductive fitness under difficult conditions.
>> Is it possible that the mechanism for this is lengthening of telomeres under
> CR, either via telomerase expression or the ALT pathway for lengthening
> telomeres seen in mice. Has anyone ever tested for telomere length extension
> in CR mice?
>> Given the heated discussions between proponents of CR and those supporting the
> telomere theory of aging in this newsgroup, it would be ironic if such a
> mechanism existed.
No, it really isn't. That's just my opinion, as I don't
know that the experiment has actually been done (and I tire
of this topic so I won't go into detail as to my reasons),
but I find it HIGHLY unlikely. And I'm not even sure that
the "making the best of a bad lot" argument holds water, for
two reasons: One, things in the wild don't really do CR,
they just starve. Two, while mice have a short enough
lifespan to have this be plausible, longer-lived mammals do
not. Unless it is just random evolutionary conservation
there is no reason that this phenomenon should apply to
animals with multi-decade lifespans, as any period of
starvation would be inconsequential to the overall length of
their reproductive period.