[Dragaera] Breaking the Cycle - Genetic Purity

[Maximilian Wilson]

On 8/28/06, Philip Hart <philiph at slac.stanford.edu> wrote:
> On Mon, 28 Aug 2006, Maximilian Wilson wrote:
> > Sounds like a good way to come out with a lot of non-Yendi
> > crossbreeds, if the Yendi male (say, Pel) passes on his non-Yendi
> > genes (say, Issola) instead.
>
> Well, it's complicated I think, and I didn't want to get into the
> whole mess since my genetics knowledge is puddle-shallow, but
> I can imagine a few scenarios: the allele in question is dominant,
> and most Yendi have two copies, in which case there would be no
> real crossbreeds.  Or many Yendi have one copy, so half of the
> children wouldn't be Yendi.  But those children wouldn't come back to
> House Yendi, keeping things pure on that side.

Dragaeran genetics may be totally different from genetics as we know
it, but this doesn't make any sense under Mendelian genetics. If the
allele in question is dominant, and a Yendi has two copies, yes, if he
has a child with an Issola, the child is guaranteed to have a Yendi
gene and a (hypothetical) Issola gene. But now his child doesn't have
two copies of the Yendi gene, so there's an even chance that when the
child mates with (say) a Dzur, you'll get a Dzur/Issola crossbreed
instead of a Dzur/Yendi=Yendi. The only way to get two copies of the
Yendi gene is to breed a Yendi with a Yendi, and cross your fingers
(hoping that no recessive traits are getting passed on instead). If
Yendi is the dominant gene, it will be very hard to purge recessive
non-Yendi traits from the gene pool.

> Anyway, the idea demands that there be a noticeable but not easy to
> trace effect - a very Yendi sort of thing - so that there's anger
> but no outright excuse to kill all the snakes.  If your child doesn't
> really excel as a whatever-you-are, maybe you blame the Yendi.  If
> your child just coming into adulthood leaves one day without explanation,
> or upon saying he has certain issues of a personal nature he doesn't
> care to discuss, maybe you blame the Yendi...

The effect you describe can't come from Mendelian genetics, but you
might follow Greg Cochran's route and postulate that Yendi-ness is the
result of a pathogen infecting an existing embryo, rather than part of
the DNA. Then you get to hijack the existing genes without worrying
about dominant/recessive traits. Basically, Yendi-ness results from
your mom catching an STD; alternatively it could be something you
catch yourself in early development.

-Maximilian

[Cochran's idea is that if you take evolution seriously, not many
diseases can be genetic in origin because they'd quickly get bred out
of the gene pool; therefore we should be looking for environmental
causes like pathogens, which are transmitted independently of host DNA
and therefore not subject to evolutionary pressure in the same way.]

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Be witty if you can,
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