India is 'thailand' to Asia, say scientists

By Raja Murthy

MUMBAI - Since "thai" means "mother" in classical Tamil, the language of the south Indian state of Tamil Nadu and said to be the oldest living language in the world, "thailand" means motherland. However, India could be an ancient "motherland" of Thailand and Asia in a more literal sense, according to a new investigative study, "'Mapping Human Genetic Diversity in Asia".

The findings, from an unprecedented collaboration of over 80 researchers and 40 scientific institutions across Asia [1], reveal a twist in the history of human migration. It points to India, then Thailand and Southeast Asia, being the ancestral home to most Asians.

The paper, titled "Mapping Human Genetic Diversity in Asia", published in the Science journal issue of December 10, is the first of its kind on Asian populations. Undertaken by the Singapore-based Human Genome Organization (HUGO), the study follows earlier multiple genetic studies on European populations.

The HUGO Pan-Asian SNP Consortium, as the project is called, overturns accepted knowledge that multiple migrations of populations directly went to East Asian countries from Africa, nearly a hundred thousand years ago.

According to the new study, Dravidians - the race of people who inhabit south India, including Tamils - could be a common ancestral link to most modern-day Asians.

The news would be an early mega Christmas gift to chauvinistic Dravidian political parties, such as the Dravida Munnetra Kazhalgam (DMK, or the Dravidian Progressive Party) and its 85-year-old chief, Muthuvel Karunanidhi, currently ruling Tamil Nadu.

Historically, Dravidians are considered India's original settlers. A more disputed theory says Dravidians were the original inhabitants of the Indus Valley civilization. Aryan invaders from Europe pushed them south of the Vindhaya Mountains into the Deccan Plateau in southern India, over 3,500 years ago.

But while the new HUGO study could support anthropological knowledge of Aryans invading India, the findings also say modern India shares a closer genetic ancestry with Europe than with Asia. "Most of the Indian populations showed evidence of shared ancestry with European populations," observed page four of the six-page report in Science.

"The current Indians received more genetic input from Aryan invasions which brought more Caucasian genes," says Dr Edison Liu, executive director at the Genome Institute of Singapore and president of HUGO. "So in fact, excluding modern-day Indians, there is clear indication that we are all genetically related in Asia."
Modern-day Indians, Liu says, would mean those in post-Aryan India. In effect, the new HUGO study could point to India having a large Eurasian population, like Russia.

"We have redefined the genetic history of Asian migration," declared Liu. "Previously, it was thought - because of archaeological, anthropological, and limited genetic data - that Asia was populated by two waves of migration. One wave was from Southeast Asia, called the Southern route, and the second from Central Asia, called the Northern route."

Liu informed Asia Times Online that the HUGO Pan-Asian SNP Consortium findings now point to a single wave of migration from Southeast Asia. "This places disparate ethnic groups like the Negritos [in the Philippines], Dayaks [in Borneo, Indonesia] etc. within the Asian fold," says Liu. "The reconstruction is out of Africa to India."

Caucasians and Asians were then divided, with the Caucasians moving to the Levant, or the Asian side of the Mediterranean Sea. The people wave continued to India, and then to Thailand, Malaysia, Indonesia and Philippines. From Southeast Asia, settlers migrated to other parts of Asia, including China.

If the study is accurate, the Han Chinese - the single-largest ethnic group in Asia and in the world - have ancestral linkages to southern China, northern Thailand and earlier in India.

Sections of the Indian media highlighted the Chinese angle in the HUGO report. The Times of India, with a readership of 13.3 million, headlined its report as "Ancestors of Chinese came from India: Study". The Mumbai-based Daily News and Analysis went further, calling its report "The Chinese evolved from Indians: Study".

So do Chinese have Indian ancestors? "It is probably more correct to say that Dravidians [in southern India] and Chinese had common ancestors, than to say that Chinese ancestors originated in India," said Liu, who was born in Hong Kong and emigrated to the United States in 1957.

"What we are seeing is the transit of our ancestors in their travels out of Africa through India and into Southeast Asia and North Asia," Liu explained. "Along the way, they deposited progeny that later expanded, or contracted."

Benefits from the findings include unified health solutions across Asia. A common ancestral link enables clinical trials for medicines that would be applicable across a wider region. Liu has worked on leukemia and breast cancer research at the University of North Carolina at Chapel Hill.

"This research is also significant for furthering the research in medicine," Samir Brahmachari, director general of the New Delhi-based Indian Council of Scientific and Industrial Research, told Indian media.

"The findings have great potential for collaboration with these countries in finding treatment to many diseases like flu, HIV and other pandemics," said Brahmachari, who is also a member of the 18-person HUGO governing council, and a professor of molecular biophysics and genetic engineering.

"The paper not only presents a fantastic genotype database but also provides vital clues to scientists of diverse fields - from linguistics to archeology to human genetics," says Vikrant Kumar, a post doctoral fellow of the Genome Institute, Singapore, and an investigator in the study.

Kumar, who earned his doctorate from the University of Calcutta, calls this the only effort of its kind where 73 populations scattered across 10 Asian countries are studied together. About 2,000 samples covering almost the "entire spectrum of linguistic and ethnic diversity" were genotyped for about 50,000 single nucleotide polymorphic markers, [2] he said.

Apart from redefining the migratory origins of Asian people, the HUGO project marked a new high in pan-Asian scientific collaboration. "This study was very unusual," Liu says. "Perhaps the proudest achievement was that 10 Asian countries mounted this study on our own steam, funded and completed it internally, with each member working as equal partners."

Liu, whose academic career includes stints at Washington University, Stanford University, University of California and University of North Carolina, calls this study a "milestone not only in the science that emerged, but the consortium that was formed. We overcame shortage of funds and diverse operational constraints through partnerships, good will, and cultural sensitivity."

One of the hurdles was the disparity in technological access among the project team in various countries, with their varying access to expensive technologies. The problem was resolved by developing a host-guest structure, in which the technologically better off countries hosted working scientists with lesser technology access.

"We transferred technologies, expanded capabilities, forged friendships and now have an Asian scientific network of considerable worth," says Liu, a nice enough initial outcome of a project that found a common ancestral link to Asians.

Notes
1. Apart from over 80 individual researchers and scientists, the project involved 40 leading scientific organizations in Asia. It included Malaysia's Human Genome Center in Kelantan; India's Council for Scientific and Industrial Research in New Delhi; Thailand's National Center for Genetic Engineering and Biotechnology in Pathumtani; the Korean BioInformation Center in Deajeon; the University of Philippines in Manila; Taiwan's Institute of Biomedical Sciences; the Genome Institute of Singapore; Japan's National Institute of Genetics and the Chinese Academy of Medical Science.
2. A genetic marker, a gene or a known DNA sequence in a chromosome (a chromosome is a DNA unit found in cells), can be detected in the blood and are generally used to see if an individual or a group are vulnerable to a particular disease. A genetic marker may be a short DNA sequence (single nucleotide polymorphism or SNP), or a long DNA sequence.

The shorter SNP (pronounced snip) - used in this study - refers to a variation of genetic traits within an individual or a group. The study used 54,974 SNPs from 1928 persons representing 73 Asian populations. SNPs are the most frequent type of DNA variation. The HUGO study used the 'Affymetrix GeneChip Human Mapping 50K Xba Array' technology to analyze SNPs. The Affymetrix technology is available to scan SNPs of various densities, from 10,204 SNPs to a million.

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