March 15, 2012. Copyright 2012, Graphic News. All rights reserved

Cosmopolitan ice-age may have led to todayÕs humans

LONDON, March 15, Graphic News: 
By about 20,000 years ago, modern humans had made their way out of Africa and replaced their distant cousins -- the more primitive populations of humans -- living in Europe and Asia. However, until now, the details of this transition have been sketchy.

A new study by John Stewart of Bournemouth Universtity and Chris Stringer of the Natural History Museum in London is painting a clearer picture of the way in which modern humans took over from their ancient ancestors, such as the Neanderthals and Denisovans, in Eurasia.

The authors compiled genomic data on these two ancient human populations and coupled them with studies of other organisms that persisted over many glacial cycles. They then used that information to create new models of the massive human migration from Africa, which began approximately 100,000 years ago.

These models suggest that ÒrefugiaÓ, or locations that harbour relict populations of a once-widespread species, were important in determining the pace and pattern of this modern human takeover. Their models demonstrate how a refuge in a particular part of the world can lead species to important evolutionary changes, including the creation of new species altogether. The research appears in the March 16, 2012 issue of Science.
/ENDS