More on Early SEA Dispersals

The international team that conducted the study on Sundaland flooding and population dispersal in Southeast Asia has released some new press releases. I wonder if a complimentary study using Y chromosome data is in the works.

Regards,
Paul Kekai Manansala
Sacramento

The researchers show that population dispersals came earlier, from within the region, and probably resulted from flooding.

The conventional theory, or the ‘out of Taiwan’ model, suggests that the current day populations of Island Southeast Asia (ISEA) originate in a Neolithic expansion from Taiwan, driven by rice agriculturalists about 4,000 years ago. This theory was contested 10 years ago by Oxford University scientist, Dr Stephen Oppenheimer, in his book Eden in the East: The Drowned Continent of Southeast Asia, when he suggested the migrations came from within ISEA and resulted from flooding in the region.

This latest study, led by Leeds University and published in this month’s Molecular Biology and Evolution, shows that a substantial fraction of the mitochondrial DNA lines (inherited by female descendants) have been evolving within ISEA for a much longer period, some since modern humans arrived about 50,000 years ago. The DNA lineages show population dispersals at the same time as sea level rises and also show migrations into Taiwan, east out to New Guinea and the Pacific, and west to the Southeast Asian mainland – within the last 10,000 years.

Study co-author Dr Oppenheimer, from the Oxford University School of Anthropology, said: ‘One of my main predictions in the book was that three major floods following the Ice Age forced the inhabitants to escape in boats and flee to less flood-prone regions. By examining mitochondrial DNA from their descendants in Southeast Asia and the Pacific, we now have strong evidence to support the flooding theory and this is possibly why Southeast Asia has a richer store of flood myths, more than any other region in the world.’

Martin Richards, the first Professor of Archaeogenetics at Leeds University, who led the interdisciplinary research team, said: ‘I think the study results are going to be a big surprise for many archaeologists and linguists, on whose studies conventional migration theories are based. These population expansions had nothing to do with agriculture, but were most likely to have been driven by climate change, in particular global warming and the resulting sea-level rises at the end of the Ice Age between 15,000 to 7,000 years ago.’

Source: Oxford News

Climate Change, Sundaland and Human Migration

A March 2008 study provides some of the first genetic evidence of human migration apparently caused by the submergence of Sundaland starting at the beginning of the current warm Holocene period.

MtDNA haplotype E reached Taiwan and the Western Pacific from Sundaland within the last 8,000 years. From a practical standpoint it would be difficult to conceive that the vast sea flooding of the continent would not have spurred extensive demographic movements. Stephen Oppenheimer, whose book "Eden in the East," studied the evidence for such migrations, is one of the contributing authors of this study published in the journal Molecular Biological Evolution.

Regards,
Paul Kekai Manansala
Sacramento

Mol Biol Evol. 2008 Mar 21

Climate Change and Post-Glacial Human Dispersals in Southeast Asia.

Soares P, Trejaut JA, Loo JH, Hill C, Mormina M, Lee CL, Chen YM, Hudjashov G, Forster P, Macaulay V, Bulbeck D, Oppenheimer S, Lin M, Richards MB.

Institute of Integrative and Comparative Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.

Modern humans have been living in Island Southeast Asia (ISEA) for at least 50,000 years. Largely because of the influence of linguistic studies, however, which have a shallow time depth, the attention of archaeologists and geneticists has usually been focused on the last 6000 years - in particular, on a proposed Neolithic dispersal from China and Taiwan. Here we use complete mitochondrial DNA (mtDNA) genome sequencing to spotlight some earlier processes that clearly had a major role in the demographic history of the region but have hitherto been unrecognised. We show that haplogroup E, an important component of mtDNA diversity in the region, evolved in situ over the last 35,000 years and expanded dramatically throughout ISEA around the beginning of the Holocene, at the time when the ancient continent of Sundaland was being broken up into the present-day archipelago by rising sea levels. It reached Taiwan and Near Oceania more recently, within the last approximately 8000 years. This suggests that global warming and sea-level rises at the end of the Ice Age, 15,000-7000 years ago, were the main forces shaping modern human diversity in the region.

Environmental factors in circum-Pacific migrations

A new study examines the environmental factors that impacted human migrations in the circum-Pacific region.

This study covers the period of Sundaland flooding that started during the present inter-glacial period known as the Holocene. Some of the migrations would coincide also with the Nusantao movements throughout much of the circum-Pacific and the earlier Austric dispersions in Southeast Asia.

Warming temperatures caused ice sheets to melt and sea levels to rise but these eventually leveled off. Recently, human-driven global warming has caused sea levels to be begin rising again.

Contact: Davina Quarterman
davina.quarterman@oxon.blackwellpublishing.com
01-865-476-307
Blackwell Publishing Ltd.

Environmental setting of human migrations in the circum-Pacific Region

A new study by Kevin Pope of Geo Eco Arc Research and John Terrell of The Field Museum adds insight into the migration of anatomically modern humans out of Africa and into Asia less than 100,000 years before present (BP). The comprehensive review of human genetic, environmental, and archaeological data from the circum-Pacific region supports the hypothesis, originally based largely on genetic evidence, that modern humans migrated into eastern Asia via a southern coastal route. The expansion of modern human populations into the circum-Pacific region occurred in at least four pulses, in part controlled by climate and sea level changes in the Late Pleistocene and Holocene epochs. The initial “out of Africa” migration was thwarted by dramatic changes in both sea level and climate and extreme drought in the coastal zone. A period of stable climate and sea level 45,000-40,000 years BP gave rise to the first major pulse of migration, when modern humans spread from India, throughout much of coastal southeast Asia, Australia, and Melanesia, extending northward to eastern Russia and Japan by 37,000 years BP.

The northward push of modern humans along the eastern coast of Asia stalled north of 43° N latitude, probably due to the inability of the populations to adjust to cold waters and tundra/steppe vegetation. The ensuing cold and dry Last Glacial period, ~33,000-16,000 year BP, once again brought dramatic changes in sea level and climate, which caused abandonment of many coastal sites. After 16,000 years BP, climates began to warm, but sea level was still 100 m below modern levels, creating conditions amenable for a second pulse of human migration into North America across an ice-free coastal plain now covered by the Bering Sea.

The stabilization of climate and sea level in the early Holocene (8,000-6,000 years BP) supported the expansion of coastal wetlands, lagoons, and coral reefs, which in turn gave rise to a third pulse of coastal settlement, filling in most of the circum-Pacific region. A slight drop in sea level in the western Pacific in the mid-Holocene (~6,000-4,000 year BP), caused a reduction in productive coastal habitats, leading to a brief disruption in human subsistence along the then densely settled coast. This disruption may have helped initiate the last major pulse of human migration in the circum-Pacific region, that of the migration to Oceania, which began about 3,500 years BP and culminated in the settlement of Hawaii and Easter Island by 2000-1000 years BP.

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Regards,
Paul Kekai Manansala
Sacramento