poly: Re:gene selection/design

From: d.brin <brin@cts.com>
Date: Fri Feb 27 1998 - 16:00:37 PST

Carl said:>>Something close to it is close to possible: sperm selection.
If it were
possible to sort sperm according to which genes they contained, one would
be halfway toward the Heinleinian method. It has been feasible to sort
cells according to their surface proteins for twenty-five years. It has
been feasible to sort sperm by whether they contain a Y chromosome for
about two years (sorry, no reference-- somebody at the veterinary school of
the University of Texas developed this). I would not be terribly surprised
if someone announced a method of sorting sperm according to whether they
contained a given allele, either of a particular gene of interest or of a
nearby marker gene. It's not quite as good as the Heinleinian method,
since it doesn't let you pick the egg, and it doesn't give you the ability
to select among all possible arrangements of paternal genes. In order to
have an adequate number of sperm left after the selection, you could
probably only select for a dozen or two genes at most. But compared to
methods requiiring in vitro fertilization, it is much less invasive, and
potentially far cheaper.

Good thoughts. I'd certainly be interested in learning more about the
recent sperm sex-sifting method. (Not for personal reasons, we have 2 boys
and a girl.) Here's a quirky thought though. I hear that I am one of the
few members of the Caltech class of 73 to have a daughter! Nearly all boys.
Yet, among TopGun fighter jocks, it's the opposite. All the Right Stuff
guys tend to have girls. A function of sedentary vs accelerated

 I hear that older, centrifuge-based, preselection methods are used in the
Macho-Belt and East Asia to select for boys, but those few who use it in
the US are mostly seeking the opposite sex of whichever child they already
have. Speaks volumes, socially.

But now imagine this. What if one could come up with a birth control pill
that macho husbands would not only approve of, but be willing to take!
Currently, contrception is stymied in some areas by belief that many
offspring is a measure of virility. But what if there were a pill that a
man could take to kill off all his gynosperm? (The ones carrying an X
chromosome.) If it ensured he'd have only male offspring the results
donwstream would be remarkable!

        1) A lowered near-term birthrate, since overall fertility would
decline if there's less sperm.
        2) A massive tilt in birth gender ratio, far greater than now seen
in asia.
        3) A downstream decline in fertility due to lessened supply of wombs.
        4) Possible profound changes in perceived value of women leading
either a) to their gaining respect or b) to becoming fiercely defended
        5) A huge supply (in a decade or two) of frustrated males....
The potential for interesting scenarios is substantial!

Re: the Heinlein solution, I urge you to get Beyond This Horizon and see
how Heinlein explains it. He was deeply concerned about
Heisenberg-interference effects, in probing-analyzing germ cells down to
the molecular level, one-by-one, going through millions to find the right
one. He partly solved this by not looking at the ova, but instead at the
polar body haploid cell that's spun off during meiosis, which contains the
complementary OPPOSITE set of chromosomes from the ovum. I forget how he
dealt with sperm, but clearly he intended not just to sift chemically for
the presence of a few alleles, but to look-examine every single sperm in
detail and select out the best.

 Excellent point re: positional goods. A basketball giant arms race would
be silly.

Received on Fri Feb 27 23:56:03 1998

This archive was generated by hypermail 2.1.8 : Tue Mar 07 2006 - 14:45:30 PST