[7] Reich is currently a geneticist and professor in the department of genetics at Harvard Medical School, and an associate of the Broad Institute, whose research studies compare the modern human genome with those of chimpanzees, Neanderthals, and Denisovans.
[citation needed] Reich's research team at Harvard University has produced evidence that, over a span of at least four million years, various parts of the human genome diverged gradually from those of chimpanzees.
[10] The split between the human and chimpanzee lineages may have occurred millions of years later than fossilized bones suggest, and the break may not have been as clean as previously thought.
[14] A follow-up study by Moorjani et al. (2013) revealed that the two groups mixed between 1,900 and 4,200 years ago (2200 BCE–100 CE), after which a shift to endogamy took place and admixture became rare.
[15] Metspalu et al. (2011), representing a collaboration between the Estonian Biocenter and CCMB, confirmed that the Indian populations are characterized by two major ancestry components.
[17] Reich's research team significantly contributed to the discovery that Neanderthals and Denisovans interbred with modern human populations as they dispersed from Africa into Eurasia 70,000–30,000 years ago.
[18] Reich's lab received media attention following its discovery of a genetic marker which is linked to an increased likelihood of developing prostate cancer.
"[20]Reich in 2018 demonstrated based on genetic evidence, West Asian geneflow into modern Afro-Asiatic speaking African populations could support a diffusion of these languages from the Middle East: "New insights are already emerging from ancient DNA, which makes it possible to document ancient migrations between the Near East and North Africa that could have spread languages, culture, and crops.
Our work also found strong evidence for a second wave of West Eurasian-related admixture this time with a contribution from Iranian-related farmers as might be expected from a spread from the Near East in the Bronze Age-and showed that this ancestry is widespread in present-day people from Somalia and Ethiopia who speak Afroasiatic languages in the Cushitic sub-family.