Indians make up one of the major human ancestry groups, with relatively little genetic differentiation among people from different parts of the country, according to a new study conducted in the US. "We were struck both by the low lewel of diversity amongst people spanning such a large geographical region, and that by the fact that people from the Indian sub-continent constituted a distinct group when compared to populations from other parts of the world" says Pragna Patel, who led the study.
And this is from the synopsis of the report
"....The authors performed an extensive investigation of Indian genetic diversity and population relationships, sampling 15 groups of India-born immigrants to the United States and genotyping each individual at 1,200 genetic markers genome-wide. Populations from India, and groups from South Asia more generally, form a genetic cluster, so that individuals placed within this cluster are more genetically similar to each other than to individuals outside the cluster. However, the amount of genetic differentiation among Indian populations is relatively small. The authors conclude that genetic variation in India is distinctive with respect to the rest of the world, but that the level of genetic divergence is smaller in Indians than might be expected for such a geographically and linguistically diverse group.
Ha! More ammo. You can read the full PSoS Genetics report here