Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!boulder!pell
From: pell@boulder.Colorado.EDU (Anthony Pelletier)
Newsgroups: sci.bio
Subject: Re: Hybrid vigor
Summary: Long ramblings (as usual)
Message-ID: <10659@boulder.Colorado.EDU>
Date: 10 Aug 89 21:55:44 GMT
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Reply-To: pell@boulder.Colorado.EDU (Anthony Pelletier)
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> neal@lynx.uucp (Neal Woodall) writes:
>> Mr. Casseres is clearly ignorant on this: hybrid vigor can indeed be 
>applied
>> to things other than agricultrual crops.....it is also frequently 
>applied to
>> agrcultural stock (ie, animals) as well. Perhaps the reason you hardly 
>ever
>> hear of it being aplied to humans is because it invariably causes a 
>furior

(David Casseres) writes:
>Well, EXCUSE ME for saying something is racist.  I guess nobody should 
>ever call anything racist again, ever (except affirmative action), for 
>fear of making non-progressives afraid to talk.  Give me a break, Neal.
>

Good response dave...if you can't address the point (that you were incorrect
in your claims about hybrid vigor) slander the other guy and drag in emotional
issues.
I should add that I don't think Hybrid vigor is the reason for the phenominon
we are discussing since it really only applies to the "F1" generation.
For each ensuing generation the chance of being homozygoes for a deliterious
allele starts to go up again.

I think the first point to make is that there are differences--average
height, bone density etc.--between races.
One poster has pointed out that the difference among people of a given
race can be more than that between races.  That is certainly true.
The bell curves certainly intersect over most of their volume--but we are not
talking about the average here.  We are talking about world class atheletes;
I expect them to be several standard deviations off the mean for many things.
Statistics will tell you that for two normal curves displaced even by a
small amount, the points at the leading edge of one will be farther out
than those of the the other.  Or, for a given point on the X-axis, there will
be more representitives in one group than the other.  

Take for example the question raised by one poster of why long distance
runners are predominantly white and sprinters are predominantly black
(kenyan's notwithstanding).
You might also notice that there are distict differences in body type
between the two groups of atheletes--the sports put different demands on
the atheletes.  Why is it racist to suggest that one body type is found
more often in one race than the other?

The basis of the expression of genetic differences is simple biochemistry.
There is no racism invoved to say, for example, that scicle-cell anemia
exists only in people of African desent.  A particular variant of hemoglobin
that is found (so far) only in blacks is the cause.  But other traits about
which we are speaking can be described as simple biochemical differences
(arising from genetic differences).

The action of muscle is pure biochemistry.  I won't go into details of
the contraction cycle.  But, suffice it to say that each myosin head must
cycle many times to move a muscle at all.  The rate at which each myosin
head can be re-set and therefore re-cycle sets a built-in limit
on contraction velocity.  Things that make the cycle go more quickly would
tend to make the velocity of contraction greater.
Consider a hypothetical example:
If there were two common variants of Myosin Light-chain Kinase, one with a
high Vmax and high Km(ATP), the other with the oposite profile, people with the
former could contract the muscle with greater velocity, exerting
greater thrust, but would fall below optimal ATP concentrations very rapidly
during prolonged use; while people with the latter form would not be able to
exert nearly the thrust, but could keep going longer.
Let's assume that things like drive to succeed and commitment to training
and all those things are equal; the first group would be better sprinters and
the second group would be better marathoners.

So, what if, as for hemoglobin, one isoform exists at higher frequency
in the black population than in the white?  So What?
Is this notion really so disturbing?  Why should we treat it differently
than, say, the difference in isoforms of Aldehyde Dehydrogenase between
Whites and Asians? (Many Asians have a slow form that leads them to be
sensitive to drinking alcohol)

Now, no one trait is going to "make" you an athelete, or an athelete
of a particular kind.  It is more complex than that.  But certain traits
that have a genetic component make a person more suited to one sport or another.
Sports represents a form of selection.  You don't see many hemopheliac boxers,
unless you count Jerry Quarry--but perhaps that makes the point.  He was
a good athelete whose skin was not tough enough to stand up to a punch,
so he did not make it.  Would it bother anyone if black skin was more dense
with connective tissue and did not cut as easily?  It wouldn't surprize me.
The same selection that gave rise to greater melanin deposition (intense
solar radiation) might also select for "thick" skin.

So the point is that, to the extent the "races" still are not freely
interbreeding (they are not, though one hopes those social tenets will
fall), there will be some traits that will tend to assort with skin type.
This really should not be considered racist. As long as we treat people
as individuals to be viewed for their own merits, rather than the embodiment
of statistical averages, we are not being racist.
And we can keep open discusions of how genetics influences what we are.

-tony