"...at Y-chromosome and mtDNA. Just two genes out of the 40,000 or so we have." -ttnz
Terry, you're mixing metaphors (chromosomes & genes). I'd think it was more like 1 or 2 out of ~50.
What about my above questions on post #21471, "...considered the idea of this 'robustness' simply being a response to the environment?"
If my memory is correct, a 0.1% adaptive advantage can spread to 95% of the population after about 100 generations; and a 0.5% advantage takes only 20 generations to spread like that.
Also, I think our ideas of "immigration" may be too limited. We spread (well, the fitter ones did) and we traded; but I doubt there was much casual immigration (only forced -for various reasons).
Just speculating at this point, so...later!
I like your ideas (on both threads) and agree with much (except some definite conclusions), but I think there are more external influences, as well as genetic plasticity and options, than we yet realize.
~~SA
