On Wed, 14 Mar 2001, Dr. Joyce Johnson wrote:
<snip>
> My "wonderment" concerns the amount and location of genetic
> material on the y chromosome. If we conceptualize (pun unintended) the y
> chromosome as a "short x," then wouldn't it be possible for the length of
> the y chromosomes to vary? and thereby vary in genetic information to
> complement the x?
<snip>
> Why do I think there could be variations in length of y?
<snip>
> Is anyone aware of research on variations in the length and
> contents of the y chromosome, and its effects on development?
Sorry to truncate Joyce's post so severely but I really just
wanted to respond to the final query. In searching for something
else, I came across a recent item from _Science I'd tucked away
on the Y. I don't entirely follow it, but it seems to be on the
topic that concerns Joyce.
It's called "The why behind the Y chromosome" (G. Vogel,
_Science_, 286, 877-78) and reports on a research report on p.
964 (which I didn't keep probably because I couldn't understand
it). It reports research suggesting that the Y chromosome may
once have been as large as the X, but progressively shrank. The
article gives a neat diagram of the X, showing the hypothesis
that the Y diverged in four stages, and that only a tiny part of
the short arm can still recombine with the X.
Go get it, Joyce!
-Stephen
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Stephen Black, Ph.D. tel: (819) 822-9600 ext 2470
Department of Psychology fax: (819) 822-9661
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