quote:
However if the environmental pressure were removed would the populations not tend to rebound toward their predivergent state?
Which would tend to eradicate the mutation from the population or store it in a dormant state within the population.
Yes. The environment has changed (albeit back) so the result
would be for the trait frequencies to re-align. Unless of course
the environmental change lasted for a number of generations, during
which time some or all of the original traits were lost from the
genome ... then there is no going back.
Accepting that trait frequencies fluctuate with changing environmental
pressures is something we appear to agree on though.
quote:
If this is the case is it not possible that genetic information has always had messages in dormant states waiting to be turned on when
environmental conditions were right and off when they were not?
Unlikely when you view the effects of selective breeding.
Traits are picked by the breeder and bred for, resulting in
a huge diversity in, say, dogs. If left to their own devices
(as in Portugal for example, where dog packs roam the streets
reasonably freely and have done so for some time), there is still
wide diversity ... even after much inter-breeding.
This suggests that traits are not 'switched off' or 'made dormant'
but are irrevocably changed (although there is some emerging evidence
for re-evolution in insects I believe).
quote:
Yes, selective breeding has led to a vast diversity of
domesticated animals. If left to nature would they not reach a state of equilibrium in their genetic material?
See above for why I find this unlikely, feral cats in the UK are
another example that springs to mind. They still show the
domestic breed varieties (in various mixtures), but have in some
areas been left to 'nature' for many generations.
Selective breeding indicates that changes can be 'selected'
into the genome in a manner that does not allow for an easy
route back to the start point.
Of course no new species have been created via selective breeding
(that I am aware of) so that still remains another issue.
The implicaiton of mules and ligers, though, is divegence to
the point where biologists would classify the critters as
separate species ... but that's just my opinion.