Control Freaks Unite

[Thomas Daniel <danielt@u.washington.edu>]

UW   MATHEMATICAL BIOLOGY SEMINAR PROUDLY PRESENTS

A DOUBLE HITTER

Jamie Theobold speaks the second time this year at 1230 Wed and Friday
in 114 Kincaid


Please come!!!



A DYNAMIC OPTIMIZATION MODEL OF THE FITNESS CONSEQUENCES OF NATURAL
CALORIC RESTRICTION

It has now been over sixty years since McCay et al. (1935, 1939) first
reported that restricting the food intake of rats had the remarkable
effect of increasing their lifespans and retarding the onset of many
diseases.  Since this time, abundant studies have described this and
many
other responses caloric restriction in a variety of species (see
Weindruch
and Walford 1988), but the mechanisms remain largely a mystery, and no
other treatment has been found to produce similar effects to the same
degree.  Still, the variety, magnitude, and ubiquity of age-retarding
effects of caloric restriction are so impressive that many investigators

assume this response is an evolutionary adaptation, selected to help
animals outlive times of food shortage.

I performed selected experiments on wild house mice (Mus musculus) and
then constructed a dynamic optimization model (Mangel and Clark 1988) to

explore the plausibility that the anti-aging response to caloric
restriction may be an evolutionary adaptation.  The computer model
provides an experimental subject unobtainable in reality: a mouse
lacking
an anti-aging response to caloric restriction.  I compared lifetime
fitness estimates of regular mice with those of hypothetical rodents
that
lacked an anti-aging response.  The model resolves the theoretical
conditions under which this response might be selectively advantageous.

My hypothesis is that long-term reactions to caloric restriction, such
as
life extension, are not adaptive in an evolutionary sense.  I believe
that
these traits are not selected in the wild; rather they are artifacts of
some other process.