Dr. David Reich from Harvard Medical School and his colleagues have produced a world map of Denisovan and Neanderthal ancestry in 120 diverse populations. Their analysis proposes that Denisovan admixture into humans occurred about 100 generations after Neanderthal admixture. Dr. Reich and co-authors collected their data by comparing known Neanderthal and Denisovan gene sequences across more than 250 genomes from 120 non-African populations publically available through the Simons Genome Diversity Project. The analysis was carried out by a machine-learning algorithm that could differentiate between components of both kinds of ancestral DNA, which are more similar to one another than to modern humans. The results, published this week in the journal Current Biology, showed that individuals from Oceania possess the highest percentage of archaic ancestry and South Asians possess more Denisovan ancestry than previously believed.