Soilguy wrote:
'The "new" colors in dogs occur too quickly for them to have arisen through mutations since domestication.'
Totally agree. I read information on the foxes years ago and the writer stated the changes started happening within just two or three generations. The genes must have already been present. Testosterone levels could well be implicated in colour change. We know that the effect of any particular gene is seldom as simple as we were taught in school.
I think change becomes rapid once selection is reduced because not only do double recessives survive, new combinations of double recessives survive. Colours and patterns that never appear in the wild population can suddenly appear. I think this is the aspect Trilobyte just can't get his head around when he demands a magical series of changes at the same point on the chromosome.
A relaxing of selection pressure, by definition, allows population numbers to build. Resources usually eventually become fewer and selection rears its head once more. Any change in selection pressure can then lead to rapid change in appearance. Punctuated equilibrium.
