A few months ago a friend tipped me off to the fact that David Reich was going to publish a paper about the genetics of Indians which he ascertained was going to model these populations as hybrids between "Europeans and Andaman Islanders." The paper is out, and my friend was roughly right. Reconstructing Indian population history:
India has been underrepresented in genome-wide surveys of human variation. We analyse 25 diverse groups in India to provide strong evidence for two ancient populations, genetically divergent, that are ancestral to most Indians today. One, the 'Ancestral North Indians' (ANI), is genetically close to Middle Easterners, Central Asians, and Europeans, whereas the other, the 'Ancestral South Indians' (ASI), is as distinct from ANI and East Asians as they are from each other. By introducing methods that can estimate ancestry without accurate ancestral populations, we show that ANI ancestry ranges from 39-71% in most Indian groups, and is higher in traditionally upper caste and Indo-European speakers. Groups with only ASI ancestry may no longer exist in mainland India. However, the indigenous Andaman Islanders are unique in being ASI-related groups without ANI ancestry. Allele frequency differences between groups in India are larger than in Europe, reflecting strong founder effects whose signatures have been maintained for thousands of years owing to endogamy. We therefore predict that there will be an excess of recessive diseases in India, which should be possible to screen and map genetically.
The paper itself is relatively tight and concise; a lot of the sausage-making is thrown into the supplementary information. This is freely available online, and in fact I would suggest that the first half of supplement 1 has more meat than the paper itself. As for that, the text is not as bold than the abstract, or the press summations which have appeared in its wake. For example, they say:
