Laboratory rodent inbreeding?

Thomas G. Lammers lammers at UWOSH.EDU
Wed Apr 26 07:21:21 CDT 2006

At 10:55 PM 4/25/2006, Ken Kinman wrote:
>In the news is a study which seems to show that aspartame probably isn't
>nearly as harmful to humans as it is in laboratory rats.  This brings up
>the problem of inbreeding in laboratory rats and mice which are commonly
>used to test such substances and then extrapolated to possible detrimental
>effects upon humans.  I am not generally challenging the use of rodents in
>medical research, but specifically our dependence on highly domesticated
>lineages of rodents.  Phylogenetically, rodents make more sense than using
>carnivores (like dogs or cats).  But still, has the genetic homogenization
>of laboratory rodents gone too far and compromised their usefulness in
>such studies?

I understand that philosophically, one wants to hold all variables but one
constant in an experiment, and so we desire to minimize or eliminate
genetic variability in laboratory organisms.  But don't we then run into
problems applying the results to a highly heterozygous out-breeding
organism?  What if we get a situation like the Southern Corn Leaf Blight
Epidemic of 1970, where we have unknowingly created a genetic uniform race
that is susceptible to certain things?  What if our lab rats were
unknowingly derived from some of the few rats in the world that would be
susceptible to aspartame or cyclamates or saccharin?  It's one thing to
make such errors when we are merely in the curiosity-driven pursuit of
understanding.  But when the results of our studies are the basis for rules
and regulations and societal action, that's another thing.

Thomas G. Lammers, Ph.D.

Associate Professor and Curator of the Herbarium (OSH)
Department of Biology and Microbiology
University of Wisconsin Oshkosh
Oshkosh, Wisconsin 54901-8640 USA

e-mail:       lammers at
phone:      920-424-1002
fax:           920-424-1101

Plant systematics; classification, nomenclature, evolution, and
biogeography of the Campanulaceae s. lat.

"Today's mighty oak is yesterday's nut that stood his ground."
                                                               -- Anonymous

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