[BenLurkin]

A derived form of MCPH1 called haplogroup D appeared about 37,000 years ago (any time between 14,000 and 60,000 years ago) and has spread to become the most common form throughout the world except Sub-Saharan Africa; this rapid spread suggests a selective sweep.[9][10] However, scientists have not identified the evolutionary pressures that may have caused the spread of these mutations.[11] Modern distributions of chromosomes bearing the ancestral forms of MCPH1 and ASPM are correlated with the incidence of tonal languages, but the nature of this relationship is far from clear.[12]

http://en.wikipedia.org/wiki/Microcephalin

[JimSEA]

Tonal languages are most common in Southeast Asia and East Asia. However, the Negritos and Australians predate forty thousand years by quite a bit. That would suggest two or more large “ waves” of settlement which is more than likely. Interesting that the Hobbits of Flores Island are thought by some to be microcephalic.

Also, Herto man from the Afar had a larger than average by modern standards brain some one hundred sixty thousand years ago. Yet the Afar region has not yielded up more than stone tools for that period. The South Africans seemed clearly ahead at that point (shell fish diet rather than genes?).

I just like reading about this and I ask questions. I’m by no means “expert”.