New research forces U-turn in population migration theory

University of Leeds ^ | May 23, 2008 | Unknown

[decimon]

Research led by the University of Leeds has discovered genetic evidence that overturns existing theories about human migration into Island Southeast Asia (covering the Philippines, Indonesia and Malaysian Borneo) - taking the timeline back by nearly 10,000 years.

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 catastophes 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).

[SunkenCiv]

Note: this topic is from 5/23/2008. Thanks decimon. Just a bit of a re-ping.

[SunkenCiv]

Fathers can be influential too
by Eleanor Lawrence

Biologists have warned for some years that paternal mitochondria do penetrate the human egg and survive for several hours... Erika Hagelberg from the University of Cambridge, UK, and colleagues... were carrying out a study of mitochondrial DNAs from hundreds of people from Papua-New Guinea and the Melanesian islands in order to study the history of human migration into this region of the western Pacific... People from all three mitochondrial groups live on Nguna. And, in all three groups, Hagelberg's group found the same mutation, a mutation previously seen only in an individual from northern Europe, and nowhere else in Melanesia, or for that matter anywhere else in the world... Adam Eyre-Walker, Noel Smith and John Maynard Smith from the University of Sussex, Brighton, UK confirm this view with a mathematical analysis of the occurrence of the so-called 'homoplasies' that appear in human mitochondrial DNA... reanalysis of a selection of European and African mitochondrial DNA sequences by the Sussex researchers suggests that recombination is a far more likely cause of the homoplasies, as they find no evidence that these sites are particularly variable over all lineages.