Asian perspectives on the origin of modern human populations

In spite of the general acceptance that modern humans (Homo sapiens) arose in Africa, information about the initial arrival and survival of modern humans in different areas of the world continues to be discovered and updated. Over the past several decades, Asia has been receiving increasing attention, particularly because it is considered the conduit through which Homo sapiens arrived in distant regions such as Western Europe, Australia, and eventually the Americas. Even more importantly, the Asian continent –– bounded by the Pacific, Indian, and Arctic Oceans and Europe to the west, includes a wide range of latitudinal, longitudinal, and even altitudinal variation –– which has major implications for human evolution.

The questions of what, where, how, and especially why with regard to our becoming “human” continue to be of great interest. This is why we continue to study closely and evaluate all the evidence on modern human origins and, specifically, how the Asian record contributes to addressing such questions. Findings from archaeology, hominin paleontology, geochronology, genetics, and paleoclimatology have all been contributing to a better understanding of the Late Pleistocene

(126,000 ± 5,000 years ago) human evolutionary record in Asia. In the attached article, authors discuss some of the big questions that paleoanthropologists are investigating across Asia: Can modern human dispersal “Out of Africa” be considered a single event occurring only after 60,000 years ago, or is the picture more complicated? By which route(s) did modern humans disperse across Asia? What was the nature of the interactions between modern humans and hominin groups already present in Asia? What role did geographic and/or paleoenvironmental variations play in modern human dispersals?

The traditional “out of Africa” model, which hypothesizes a dispersal of modern Homo sapiens across Eurasia as a single wave at ~60,000 years ago, and the subsequent replacement of all indigenous populations, is clearly too simplistic and in need of extensive revision. Important findings highlighted here include growing evidence for multiple dispersals, predating 60,000 years ago in regions such as southern and eastern Asia. Modern humans moving into Asia met Neanderthals, Denisovans, mid-Pleistocene Homo, and possibly even Homo floresiensis, combined with some degree of interbreeding (admixture) occurring.These early human dispersals, which left at least some genetic traces in the DNA of modern populations, indicate that later migrations were not “pristine” but rather that interbreeding kept occurring and re-occurring.

Science 8 Dec 2o17; 358: 1269 + the 7-page article

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