genetics

[Mark Berman]

Anne Kilmer <viceroy at gate.net> wrote in message
news:37EA90B2.8A02AD4 at gate.net...
>
>
> Jacob Groth wrote:
> >
> >    Part 1.1    Type: Plain Text (text/plain)
> >            Encoding: 7bit
> Anne Kilmer wrote:
>
> "If, however, you take all eggs and larvae into your house, lab or
> whatever, feed the larvae, and then release them in your garden, you may
> be disabling the mechanism that selects bright, careful caterpillars."
>
> I don't believe this would be the case, but even if it is, the mere
> result
> would be that these caterpillars would not have successful offspring.
> This
> would have no effect on the wild population whatsoever.  The gene that
> "disabled any mechanism" would be eliminated from the gene pool.
>
> You don't understand. Sorry. Let me try again.
> Natural selection eliminates the unfit. If we save all the offspring, it
> no longer eliminates them. Now lethal genes can be propagated.
> You may observe this happening in the human race and the species we
> choose to adopt.


Anne,

While I think you have been *right on target* with every post I've read so
far, Natural Selection DOES NOT eliminate the unfit. Natural Selection
doesn't care. We call the eliminated individuals "unfit" because they were
eliminated. It is circular and, in the end, meaningless. Environmental
mechanisms eliminate individuals that do not have the appropriate suite of
traits to deal with that particular environmental circumstance.

Now, that may sound circular as well, but it is not really. Lethal genes in
a different environment may be favorable.

The only reason I am bothering to point this out is that it seems most of
this discussion is focused on "bad" traits. Like the gene for white-spotted
black Pepper Moths. Really bad if the trees have lichens on them. But really
good if the trees are bare. Importantly, in this most famous case, **the
birds are the mechanism of selection.** Not the genes.

Generally, all of the offspring of a population combined will have all
combinations of genes in the pool. Some of these combinations will produce
more viable offspring than others. Some of the genes will reproduce better
in various combinations than others. But which combinations do better or
worse is determined by the environmental conditions they're in. There is no
way for it to be a "predictive," or "targeted" process.

This is important here because it is very likely that the combinations of
genes in the captive-bred butterflies are, on the whole, significantly
different from the wild-type. Not better or worse. Not more or less "fit"
(whatever that is). Just different. Selection in the captive-bred population
occurred under different environmental conditions. We don't need to consider
a "maladaptive" trait or any kind of "disabling mechanism." The actual
control in Natural Selection is imposed regardless of the conditions of the
genetic combinations in the population. Breeders could not even "select" for
traits that would result in "more fit" individuals to release, because we
could not appropriately predict all the vagaries of the natural environment.

I am not sure if it is clear or not (lord knows I've rambled enough about it
in the last couple of days). For the purposes of this discussion it is a
fundamentally critical point.

I'll try to shut up now! Thanks for your patience!

Mark
BUGMAN Educational Entoprises
http://www.bugs.org