In article <9405190315.AA24155 at pclsp2>,
vinz at PCLSP2.KUICR.KYOTO-U.AC.JP (Vincenzo Nardi-Dei) writes:
>>Telomeres shortening seems to be clearly implicated in regulation of cell
>ageing even though a stronger force should be the II principle of
>thermodinamic and its tendency to enthropy. Uncorrected DNA replication
>errors accumulate even affecting the same repairing system encoding
>genes provoking a cascade effect.
I don't think the entropy idea really holds water because errors would
accumulate from one generation to the next as quickly as from one
mitosis to the next. Just as lethal mutations are selected out in a
species so they would be selected out in a group of cells.
The death clock argument is the first suggested mechanism of aging that
has ever made sense to me because it explains why there are no imortal
mutants - they die of cancer before we notice they are immortal.
Looking at the way that anomolous longevity seems to have quickly evolved
in humans as soon as we found a use for grandparents suggests that it's
actually rather easy for evolution to produce longevity (experiments
with drosophelia show the same thing). To me this clearly points to
aging being a "deliberate" mechanism rather than some wear and tear thing.
Malcolm
