[gurps] BioTech-- Eugenics Question

[Susan Koziel]

--- Wyrm <wyrm.ksc at gmail.com> wrote:

> midnightwind at comcast.net wrote:
> [snip]
> > One question that might help-- does anyone know
> approximately how many generations it takes for a
> beetle species to go from flight to flightless when
> placed in an environment that is highly selective
> against flight, for example?

I'm not sure if anyone has tried that - but if you are
using molecular markers you can mutagenize beetles at
a higher then natural rate by exposing them (or their
eggs) to chemical mutagens... then given enough
beetles you'll find one with a mutation that has no
wings. Then you'd make a molecular profile of it, and
breed it back into the regular beetle population
(because you want to get rid of any other mutations it
might have that are bad) and then you'd use your
molecular profile to better define the set of genes
involved in wings. This would take 2 maybe three
generations - depending how fussy your profile is.
Then you'd breed your cleaned up wingless beetle to
other wingless beetles to get a population of wingless
beetles.

>  Does that number even
> come close to modeling a similar circumstances in
> humans?  How quickly would I have almost all 7-foot
> humans if we only allowed seven-footers to reproduce
> with each other, and nobody else?  Is it 1-2
> generations, or 10, or more?  I think probably only
> 1-2, to be honest.  

Height is a multigene thing that is largely influenced
by environment. Breeding only 7ft isn't going to
change things in one or two generations. But if you
know the profile of the trait (which for don't for
height) it would only take a couple generations. 
If you are thinking a single gene (or even something
that's a handful of genes).... coat colour, hair
colour, eye colour (these are genetically well
characterized traits... and relatively simple)... then
you can change things very quickly.

The time of ten generations has to do with developing
the genetic profile of a trait. Once you now that
profile and you now how it's passed the whole process
is much much faster. The problem is that initially you
need to cross and back cross to both find and
characterize your trait and then you need about 3
crosses to actually stabilize a single gene cross.
Each cross is a generation or so.... by generation I
mean from collecting seed to collecting seed (not
necessarily animal maturity in the case of mammals
where our eggs/sperm are mature faster then our
ability to breed does). 

If you are talking natural selection then all the info
about when the beetles breed becomes relevant.... if
you are actively choosing traits and forcing and
controlling breeding then all those problems become
non-issues. The difference is between the lab and the
wild. 

Oh - and I should mention another problem.... the
trait you see in a lab environment may not hold true
in the non-lab environment - because the way things
act in one situation may not work in another
situation. (Which explains how people can be highly
intelligent physicists but aren't intelligent at all
when it comes to asking a girl on a date.) 
-Sue
(Who seems to be missing some mail from the list)
:)