Re: longevity

J. R. Molloy (
Mon, 22 Nov 1999 10:58:38 -0800

John K. Clark posted:
>In today's issue of the journal "Nature" Pier Giuseppe Pelicci reports
>that he used genetic engineering to deactivate the p66 gene in mice.
>The resulting mice lived 30% longer than the non engineered mice.
>Doctor Pelicci suspects that the mechanism is similar to the one
>that increases longevity in mice that have a severe restriction
>of calories in their diet except there are even fewer side effects,
>the mice do no become very thin and they breed normally. He can
>not find any down side to the mice at all but he speculates there must be
>one someplace because otherwise evolution would already have found
>this fix; he thinks it might cause a very slight decrease in fertility in young
>mice but if it's there it's too small for him to see in his experiments. He
>says that the a drug that blocks the protein produced by p66 should be easy
>to find because it is similar to others that have already been found.

At first it seemed to me that Dr. Pelicci had made sense when he opined that "there must be" a down side to mice with deactivated p66 genes, "because otherwise evolution would already have found this fix."

Curt Adams, Patrick Wilkens, and Joao Pedro de Magalhaes have generously informed me concerning the limitations of Evolution in regard to fixing or optimizing individual organisms. Thanks to all.

As for the supposed ability of shorter life spans to accelerate the rate of Evolution by increasing the frequency of mutations over generations, this does not work because the attenuation of longevity which accompanies heightened mutability, in turn depresses the strength of the species (which, of course, includes individual group members), thereby rendering an over all disadvantage to short lived populations. This effect expands in species which depend on lengthened childhood (as Homo sapiens and elephants do) to reach their full (species specific) potential. I suppose that anyone well versed in complexity theory would have grokked this intuitively and quickly, but to this old head, it seemed quite counter-intuitive.

Although making mice live longer has important implications for humans (no doubt), the Doogie Mice experiments (discussed in earlier threads on this list) probably have even more importance. Some of us need to get much smarter before we get much older.
--J. R.

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