Research led by the University of Leeds has discovered genetic evidence that overturns existing theories about human migration into Island Southeast Asia
Prevailing theory suggests that the present-day populations of Island Southeast Asia (ISEA) originate largely from a Neolithic expansion from Taiwan driven by rice agriculture about 4,000 years ago - the so-called "Out of Taiwan" model.
However an international research team, led by the UK's first Professor of Archaeogenetics, Martin Richards, has shown that a substantial fraction of their mitochondrial DNA lineages (inherited down the female line of descent), have been evolving within ISEA for a much longer period, possibly since modern humans arrived some 50,000 years ago.
Moreover, the lineage can be shown to have actually expanded in the opposite direction - into Taiwan - within the last 10,000 years.
Says Professor Richards: "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 15,000-7,000 years ago."
At this time the ancient continent known as Sundaland - an extension of the Asian landmass as far as Borneo and Java - was flooded to create the present-day archipelago.
Although sea-level rise no doubt devastated many communities, it also opened up a huge amount of new coastal territory for those who survived(1). The present-day coastline is about twice as great as it was 15,000 years ago.
"Our genetic evidence suggests that probably from about 12,000 years ago these people began to recover from the natural catastrophes and expanded greatly in numbers, spreading out in all directions, including north to Taiwan, west to the Southeast Asian mainland, and east towards New Guinea. These migrations have not previously been recognised archaeologically, but we have been able to show that there is supporting evidence in the archaeological record too."
The interdisciplinary research team comprised colleagues from Leeds, Oxford, Glasgow, Australia and Taiwan. The study was funded by the Bradshaw Foundation and the European Union Marie Curie Early Stage Training program and is published in the current issue of Molecular Biology and Evolution (MBE).
(1) The importance of this flood-driven dispersal for the region's local communities was predicted ten years ago by co-author and Oxford scholar Stephen Oppenheimer, in his book Eden in the East.
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Notes to editors:
1. The paper, Climate Change and Post-Glacial Human Dispersals in Southeast Asia can be found at http://mbe.oxfordjournals.org/cgi/content/abstract/msn068v1
2. Professor Martin Richards holds a Chair in Archaeogenetics in the Institute of Integrative and Comparative Biology at the University of Leeds' Faculty of Biological Sciences. He also leads the Faculty's Archaeogenetics Research Group which studies the geographic distribution of modern human genetic variation, with the aim of addressing questions from archaeology, anthropology and history. http://www.fbs.leeds.ac.uk/staff/profile.php?tag=Richards
3. The Faculty of Biological Sciences at the University of Leeds is one of the largest in the UK, with over150 academic staff and over 400 postdoctoral fellows and postgraduate students. The Faculty has been awarded research grants totalling some £60M and funders include charities, research councils, the European Union and industry. Each of the major units in the Faculty has the highest Grade 5 rated research according to the last government (HEFCE) Research Assessment Exercise, denoting research of international standing. The Faculty is also consistently within the top three for funding from the government's research councils, the BBSRC and NERC. www.fbs.leeds.ac.uk
4. The University of Leeds is one of the largest higher education institutions in the UK with more than 30,000 students from 130 countries. With a turnover approaching £450m, Leeds is one of the top ten research universities in the UK, and a member of the Russell Group of research-intensive universities. It was placed 80th in the 2007 Times Higher Education world universities league table. The University's vision is to secure a place among the world's top 50 by 2015. ./
5. The Bradshaw Foundation supports and presents research on cave and rock art, together with DNA research on the initial human spread across continents as well as other approaches to human migration. www.bradshawfoundation.com
6. Marie Curie Early Stage Training programme forms part of the European Union's Framework 6 Human Resources and Mobility (HRM) activities and is largely based on the financing of training and mobility activities for researchers. These activities, known as the Marie Curie Actions, are aimed at the development and transfer of research competencies, the consolidation and widening of researchers' career prospects, and the promotion of excellence in European research.
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