Scientific consortium maps the range of genetic diversity in Asia, and traces the genetic origins of Asian populations
by Dr. Vikrant Kumar, Genome Institute of Singapore
As an anthropologist, I always wanted to know if Asians, known for their extensive linguistic and ethnic diversity also have a substantial level of genetic variation. In other words, do they have a common or multiple origins? Or whether the ancestors of Negritos from Philippines, Malaysia and Indonesia differ from those of their neighboring Asians? Or what binds us more: language or geography? The recent paper published in Science by the HUGO Pan-Asian SNP Consortium – Mapping Human Genetic Diversity in Asia quintessentially answers these fundamental questions which have been floating around for years.
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.
The paper stands out in its attempt to understand the peopling of Asia and their genetic relationships and in the process it not only presents a fantastic genotype database but also provides vital clues to scientists of diverse fields –from linguistics to archeology to human genetics. For example, it may be an interesting proposition for a human geneticist to examine if East and Southeast Asians share, more than expected, risk alleles associated with diseases. Likewise, it may be time for the linguists to re-look at the “birthplace” of the Austronesian linguistic family. I hope the consortium continues with their amazing endeavor and include a lot more number of important and isolated populations from whole of Asia and move beyond the analysis of Single Nucleotide Polymorphism to other kinds such as structural variations.
Please see below the fold for the official press release.
Several genome-wide studies of human genetic diversity have been conducted on European populations. Now, for the first time, over 90 scientists from the Human Genome Organisation’s (HUGO’s) Pan-Asian SNP Consortium have extended this study to 73 Southeast Asian (SEA) and East Asian (EA) populations. This human genetic mapping of Asia has important implications, especially in the further understanding of migratory patterns in human history, and for the study of genetics and diseases. The findings were published online in a report in Science on 10 December 2009.
The study, conducted within and between the different populations in the Asia continent, showed that genetic ancestry was highly correlated with ethnic and linguistic groups. There was a clear increase in genetic diversity from northern to southern latitudes. The study also suggested that there was one major inflow of human migration into Asia arising from Southeast Asia, rather than multiple inflows from both southern and northern routes as proposed before. This indicates that Southeast Asia was the major geographic source of East Asian and North Asian populations (see accompanying picture). Moreover, the geographical and linguistic basis of genetic subgroups in Asia clarifies the need for genetic stratification when conducting genetic and pharmacogenomic studies in this continent.
One of the corresponding authors, Professor Edison Liu, Executive Director at the Genome Institute of Singapore (GIS), and the President of the HUGO which initiated and coordinated this research, said, “This study was a milestone not only in the science that emerged, but the consortium that was formed. 10 Asian countries came together in the spirit of solidarity to understand how we were related as a people, and we finished with a truly Asian scientific community. We overcame shortage of funds and diverse operational constraints through partnerships, good will, and cultural sensitivity.”
Professor Liu also added that, “Affymetrix, led by Dr. Giulia C. Kennedy and based in the US, is our primary technology partner in this endeavour. We greatly appreciate their support. Our next goal is to expand this collaboration to all of Asia including Central Asia and the Polynesian Islands. We also aim to be more detailed in our genomic analysis and plan to include structural variations, as well as over a million single nucleotide polymorphisms in the next analysis.”