RE: Thoughts on SMP

[cfonda@sentientconsult.com]

>If one starts with a good group to choose from, and chooses the 'best of
>the breed' for the qualities desired (i.e., look at the guppy, betta,
>swordtail/platy) you will develop consistently good stock--the care must
>be in ruthless selection and allowing, only allowing, the best of the
>bloodlines to continue.

And all of these species have had outcrosses bred in... in fact, swordtails
are, for the most part, hybrids.  Most betta breeders (in fact, most
labyrinth breeders), occassionally outcross to protect the genetic strength
of the line.

>A closed breeding stock is superior to an 'outcrossing', except when one
>starts with a 'lethal' gene within the root stock.
I would beg to differ.  Any gene complex of greater than 15 chromosome
pairs will have, on average, at least 4 non-expressed lethals (the average
is 12 among humans).  Inbreeding greatly increases the chances that these
lethals will become expressed in later generations.  Inbreeding can improve
the appearance of stock for ~12 generations, after which it becomes very
dangerous.  This is all basic biology and genetics.
>I don't remember if was the guinea pig, or hamster one of these comes
>from South America) but the one that came from Syria--a male and one
>female ONLY, are the progenitors of all of their species in the hands of
>people today (apparently this it was almost extinct in the wild when
>caught however many years ago it was--and were never seen after the one
>collection of the 'pair'). No genetic hangups have been significant from
>one pair, except that now there are color varieties based upon selective
>breeding for characteristics.

I challenge you to double check your research there.  There are 2 species
of rodent for which there was only one pair of original parents each.
Hamsters, which have been more successful genetically than white mice, but
which are highly succeptible to digestive disorders and cancers.  White
mice are famous for their genetic problems... but are useful to science
because they are genetically homogeneous, allowing scientists to perform
experiments without having to worry excessively about the genetic
component.  Also, look at many pure-bred dogs... a number of breeds now
have many problems because of the amount of inbreeding... and nobody can
claim that aggressive selection is not performed in dog breeding.

- -- Cliff