Now a genetic study of the Indian population by an international Indian and American team supports the invasion hypothesis:
The new research reveals that nearly all Indians carry genomic contributions from two distinct ancestral populations. Following this ancient mixture, many groups experienced periods of genetic isolation from each other for thousands of years. . . .All current genetic research should carry the label, "interesting if true," but this seems like a good study, and it confirms what I think is the obvious interpretation of Indian history.
These genomic analyses revealed two ancestral populations. "Different Indian groups have inherited forty to eighty percent of their ancestry from a population that we call the Ancestral North Indians who are related to western Eurasians, and the rest from the Ancestral South Indians, who are not related to any group outside India," said co-author David Reich.