Influence of paleolithic range contraction, admixture and long-distance dispersal on genetic gradients of modern humans in Asia

Cavalli-Sforza and coauthors originally explored the genetic variation of modern humans throughout the world and observed an overall east-west genetic gradient in Asia. However, the specific environmental and population genetics processes causing this gradient were not formally investigated and promoted discussion in recent studies. Here we studied the influence of diverse environmental and population genetics processes on Asian genetic gradients and identified which could have produced the observed gradient. To do so, we performed extensive spatially-explicit computer simulations of genetic data under the following scenarios: (i) variable levels of admixture between Paleolithic and Neolithic populations, (ii) migration through long-distance dispersal (LDD), (iii) Paleolithic range contraction induced by the last glacial maximum (LGM) and, (iv) Neolithic range expansions from one or two geographic origins (the Fertile Crescent and the Yangzi and Yellow River Basins). Next, we estimated ...