The Pioneer Settlement of Modern Humans in Asia

Abstract

The SCR of the pioneer phase of the peopling of the vast territories of Asia has gained increasingly strong experimental support, thanks to recently acquired deeper phylogenetic and phylogeographic knowledge about the spread of mtDNA (and Y-chromosomal) variation in this continent. Much, if not all, of the early settlement process can be seen as a ‘fast train to Southeast Asia and Australia along the SCR’—indeed, so fast that the founder haplotypes at the base of haplogroups M, N, and R reached all major destinations alongside the route, as far down as Australia. It appears that Central Asia and southern Siberia were not involved in the initial peopling of the continent. It is also evident that the initial fast train phase was followed by a long-lasting freezing of the major geographic pools of maternal lineages in the south and further gene flows northwards from Southeast Asia and subsequently back westwards along the Steppe Belt extending from Manchuria to Europe. At present, western Siberia, the Urals, and Central Asia form a huge continuous admixture zone encompassing East and West Eurasian maternal lineages—a process that has so far had only a minimal influence on the essentially distinct autochthonous patterns of mtDNA variation in most of South Asia, East Asia, Southeast Asia, and Australasia.