[Thombo2]

"Why would the same mutation recently and independetly occur in isolated populations?"Good point.They(mutations) wouldn't occur unless the same influence(variable)were at work in the"isolated populations"that had left sub-Sahara.Rhetorical question:Is there anything that these isolated populations could have had in common to explain the scientists theory?

[Domestic Church]

"Rhetorical question:Is there anything that these isolated populations could have had in common to explain the scientists theory?"

Why assume they were isolated populations?

One of the funny discoveries in my 100% Celtic family from the genome project was shared genetic history with 40% of the population of Japan. Both cultures were seafaring but who would have thought 20-30 thousand years ago they sailed (or traveled on land) that far?!

[SuzyQue]

Good point.They(mutations) wouldn't occur unless the same influence(variable)were at work in the"isolated populations"that had left sub-Sahara.Rhetorical question:

Mutations don't occur because of a particular influence or variable; they survive and increase in the population if they confer a benefit (or sometimes have a neutral effect). Perhaps I misunderstood your point.