Evidence against a pre-programmed limit to life span

Robert Bradbury bradbury at sftwks.UUCP
Fri Oct 23 22:37:17 EST 1992

Science (V258:10/16/92) has a comment (p398-99) and two articles
(p457-61, 461-63) which provide strong evidence against a programmed
limit to life span.  Experiments were done on large (1.2 million) medfly
cohorts and 4 inbred Drosophila strains and 6 F1 crosses.  In both cases
they show that the increase in age specific mortality rates levels off or
shows large fluctuations in elderly populations.  This contradicts the
programmed limit theories which predict that age-specific mortality rates
should increase continually with age.  In my opinion, it also argues quite
strongly for genes which are initially neutral or good but later have
bad effects leading to death among large fractions of a population
(e.g. early onset of maturity leading to increased breast cancer,
higher iron intake leading to iron-overload, etc).  After these genes
have been elimiated from the population, the survivors die off at random
rates due to declines in gene/organism function from random mutations.

This is not news for those who have read "The Biology of Life Span:
Quantitiative Approach" by Drs. Gavrilov and Gavrilova as they
have argued that the life table data does not support the idea
of life span limits.  It may come as a shock however for people
who are in the JF Fries camp who are convinced the limit for
humans is 85+/-7 years.  Ultimately it means that to extend
the human life-span we are not working against a program
designed by nature but a program which is simply incomplete.
Robert Bradbury			uunet!sftwks!bradbury

Death is an imposition on the human race, and no longer acceptable
				Alan Harrington, The Immortalist (1969)

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