human genetic diversity

Guillermo Barron gbarron at
Mon Aug 4 21:45:14 EST 1997

I wondered if  anyone on this group could answer a question from a
neophyte (graduate student in philosophy) whose understanding of genetics
does not penetrate much beyond reading Dawkins' *Blind Watchmaker* and
Dennett's *Darwin's Dangerous Idea?*

   A recent article in Canada's  *Globe and Mail* argued against incest on
the grounds that incestuous reproduction decreases genetic diversity which
many people count as a key factor in enhancing the survival of the human
species. The sociobiologist E.O. Wilson, for example, calls genetic
diversity a"cardinal value (1978)."

Now I don't know if in fact unrestrained incestuous reproduction would
occur frequently enough to affect the human gene pool in any meaningful
way.  But it does seem clear that heterogeneous mating (if I can call it
that) *is* widespread. Up until very recently most humans mated not only
within their own race but within relatively narrow tribal and geographical
limits. This has of course changed quite radically within
the last century or so with the advent of global migration.   My question
is: does mating between genetically different populations increase or
decrease diversity?   In other words, would Laplanders mating with
Yanomani, and Tibetans mating with Cherokees increase or decrease human
genetic diversity?

Note that, no matter how the genetic variation argument runs,  I don't in
any way endorse any eugenic policies or anti-miscegenation laws  (nor do I
wish to garner your support for any such dubious political ends!).  I'm
simply not sure what humans ought to do to improve human genetic
diversity, or if it's even something we should worry about.  Any  comments
or references to helpful sources (comprehensible to the layperson) would
be most appreciated.

Thank you.

Guillermo Barron

Guillermo Barron
Department of Philosophy
University of Alberta
Edmonton, Alberta,
[403] 433-3788

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