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| Genetic Insights Into The History And Diversity Of Indian People |
C. Gopinath
11/24/2009
On 15 November 2009, Dr. David Reich spoke on the above subject in Hall A of the Science Center at Harvard University, Cambridge. This was the first in the Outreach Lectures of the Department of Sanskrit and Indian Studies of Harvard University, for 2009-2010 academic year.
Welcoming the audience, Prof. Bijoy Misra, Convener of the Outreach Committee explained that these lectures, which began in 1995, were established to serve as a bridge between the Department and the larger Harvard community. Over the years the lectures have covered several aspects of Indian Studies including culture, arts, history, religion, architecture, philosophy etc. During the last three years, the lectures were on the theme of ‘Languages and Literature of India’ and helped survey the evolution and use of seventeen major Indian languages. Beginning with this lecture, a new series was being initiated on the theme of ‘Indian Society through the Ages.’
Dr. Reich’s lecture was based on a study that he undertook in collaboration with scientists from the Center for Cellular and Molecular Biology, Hyderabad, to examine human variation between groups in India based on genomes. The team studied the genetic structure of 132 individuals drawn from 13 regions in India. They belonged to 25 groups, based on language and traditional (self-declared) caste designation. The analysis used the statistical technique of principal components analysis to differentiate between the groups.
The main findings that Dr. Reich presented were that there are two ancient populations in India that are genetically distinct. He named these as ‘Ancestral North Indians (ANI)’ and ‘Ancestral South Indians (ASI)’. He found that the ANI was genetically close to Middle Easterners, Central Asians and Europeans. Both ANI and ASI were present in most Indians; ANI ancestry ranged from 39-71%. Groups with only ASI ancestry may not exist in the Indian mainland; indigenous Andaman Islanders were unique in having ASI and no trace of ANI ancestry. Dr. Reich compared the results of the Indian samples with studies of Europeans and mentioned that unlike in Europe, geography was a poor predictor of genetic structure in India.
Another interesting finding that he presented was that there were strong ‘founder effects’ in the groups; i.e., a founder or small set of people started a group, which maintained its genetic distinctness over several generations due to endogamy. He therefore argued that there will be an excess of recessive diseases in India, and it should be possible to screen and map them genetically. He also stated that there was scope for more genetic related studies of this nature in India, however, it was difficult to secure the funding required to conduct them.
Dr. Reich’s hour-long presentation was very well received by the audience. He was able to effectively communicate sophisticated scientific information to a lay audience by taking the time to explain the science and the methods of analysis in a manner that could be easily understood. Dr. Reich’s expertise and passion for the subject was evident in the presentation, which was ably supported by slides and visuals.
The talk was followed by a discussion where he responded to several questions from the audience both on the technical aspects of the study and its implications for the debate on the historical origins of the Indian people.
Interested readers who wish to learn more of Dr. Reich’s work can consult his recently published article in ‘Nature’ 24 September 2009, titled ‘Reconstructing Indian population history.’
The next talk in this series will be delivered by Dr. P. Parthasarathi, Associate Professor of History, Boston College, on ‘Indian history from 5000 BC’ on 13 December, 3-5 pm, Hall A, Science Center, Harvard University.
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