Shared and Unique Components of Human Population Structure and Genome-Wide Signals of Positive Selection in South Asia
"Knowing whether signals associated with the initial peopling of Eurasia fall within our detection limits requires additional extensive simulations, but our current results indicate that the often debated episode of South Asian prehistory, the putative Indo-Aryan migration 3,500 years ago (see e.g., Abdulla) falls well within the limits of our haplotype-based approach. We found no regional diversity differences associated with k5 at K = 8. Thus, regardless of where this component was from (the Caucasus, Near East, Indus Valley, or Central Asia), its spread to other regions must have occurred well before our detection limits at 12,500 years. Accordingly, the introduction of k5 to South Asia cannot be explained by recent gene flow, such as the hypothetical Indo-Aryan migration. The admixture of the k5 and k6 components within India, however, could have happened more recently—our haplotype diversity estimates are not informative about the timing of local admixture.
Both k5 and k6 ancestry components that dominate genetic variation in South Asia at K = 8 demonstrate much greater haplotype diversity than those that predominate in West Eurasia. This pattern is indicative of a more ancient demographic history and/or a higher long-term effective population size underlying South Asian genome variation compared to that of West Eurasia. Given the close genetic relationships between South Asian and West Eurasian populations, as evidenced by both shared ancestry and shared selection signals, this raises the question of whether such a relationship can be explained by a deep common evolutionary history or secondary contacts between two distinct populations. Namely, did genetic variation in West Eurasia and South Asia accumulate separately after the out-of-Africa migration; do the observed instances of shared ancestry component and selection signals reflect secondary gene flow between two regions, or do the populations living in these two regions have a common population history, in which case it is likely that West Eurasian diversity is derived from the more diverse South Asian gene pool."
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"According to Prof Singh, Dr Chaubey, and Dr Kumarasamy Thangaraj, another member of the team, the findings disprove the caste theory prevailing in India. Interestingly, the team found that instead of Aryan invasion, it was Indians who moved from the subcontinent to Europe. “That’s the reason behind the findings of the same genetic traits in Eurasian regions,” said Dr Thangaraj, senior scientist, CCMB."
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"Knowing whether signals associated with the initial peopling of Eurasia fall within our detection limits requires additional extensive simulations, but our current results indicate that the often debated episode of South Asian prehistory, the putative Indo-Aryan migration 3,500 years ago (see e.g., Abdulla) falls well within the limits of our haplotype-based approach. We found no regional diversity differences associated with k5 at K = 8. Thus, regardless of where this component was from (the Caucasus, Near East, Indus Valley, or Central Asia), its spread to other regions must have occurred well before our detection limits at 12,500 years. Accordingly, the introduction of k5 to South Asia cannot be explained by recent gene flow, such as the hypothetical Indo-Aryan migration. The admixture of the k5 and k6 components within India, however, could have happened more recently—our haplotype diversity estimates are not informative about the timing of local admixture.
Both k5 and k6 ancestry components that dominate genetic variation in South Asia at K = 8 demonstrate much greater haplotype diversity than those that predominate in West Eurasia. This pattern is indicative of a more ancient demographic history and/or a higher long-term effective population size underlying South Asian genome variation compared to that of West Eurasia. Given the close genetic relationships between South Asian and West Eurasian populations, as evidenced by both shared ancestry and shared selection signals, this raises the question of whether such a relationship can be explained by a deep common evolutionary history or secondary contacts between two distinct populations. Namely, did genetic variation in West Eurasia and South Asia accumulate separately after the out-of-Africa migration; do the observed instances of shared ancestry component and selection signals reflect secondary gene flow between two regions, or do the populations living in these two regions have a common population history, in which case it is likely that West Eurasian diversity is derived from the more diverse South Asian gene pool."
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New research debunks Aryan invasion theory
Published: Saturday, Dec 10, 2011, 10:30 IST
By Kumar Chellappan | Place: Chennai | Agency: DNA
By Kumar Chellappan | Place: Chennai | Agency: DNA
"According to Prof Singh, Dr Chaubey, and Dr Kumarasamy Thangaraj, another member of the team, the findings disprove the caste theory prevailing in India. Interestingly, the team found that instead of Aryan invasion, it was Indians who moved from the subcontinent to Europe. “That’s the reason behind the findings of the same genetic traits in Eurasian regions,” said Dr Thangaraj, senior scientist, CCMB."
Link
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