East Asians come from Southeast Asia?

The genetic origins of Asians – I missed out this interesting paper on account of being in Hanoi at the time, and it wasn’t until I read this news from the Philippines that I was alerted to it. The paper presents a large-scale survey of genetic diversity in Asia, and posits that there was one migration out of Africa into Asia, the East Asian populations originated from Southeast Asian ones, and there is strong relationship between language, geography and ancestry.

Who’s your daddy? Study traces genetic origin of Asian people
PIA News, 29 March 2010

Mapping Human Genetic Diversity in Asia
Science, 11 December 2009

The abstract from Science:

Asia harbors substantial cultural and linguistic diversity, but the geographic structure of genetic variation across the continent remains enigmatic. Here we report a large-scale survey of autosomal variation from a broad geographic sample of Asian human populations. Our results show that genetic ancestry is strongly correlated with linguistic affiliations as well as geography. Most populations show relatedness within ethnic/linguistic groups, despite prevalent gene flow among populations. More than 90% of East Asian (EA) haplotypes could be found in either Southeast Asian (SEA) or Central-South Asian (CSA) populations and show clinal structure with haplotype diversity decreasing from south to north. Furthermore, 50% of EA haplotypes were found in SEA only and 5% were found in CSA only, indicating that SEA was a major geographic source of EA populations.

Dr Vikrant Kumar from the Genomics Institute of Singapore posts a nice summary at the Human Genome Organisation blog:

To the best of my understanding, so far, this is the only paper where 73 populations scattered across 10 Asian countries are studied together through a massive collaborative effort of scientists from 40 institutes mostly from Asia (~2000 samples covering almost entire spectrum of linguistic and ethnic diversity were genotyped for ~50000 single nucleotide polymorphic markers). Some of the key findings of this paper are:

· East and Southeast Asians share a common origin.

· East Asians have mainly originated from South East Asian populations with minor contributions from Central-South Asian groups.

· A common ancestor of the Negrito and non-Negrito populations of Asia entered into the continent. This supports the hypothesis of one wave of migration into Asia as opposed to two waves of migrations from Africa.

· The Taiwan aborigines are derived from Austronesian populations. This stands in contrast to the suggestion that this island served as the ancestral “homeland” for Austronesian speaking populations throughout the Indo-Pacific.

· Genetic ancestry is highly correlated with linguistic affiliations as well as geography.