According to the findings of the researchers, many pedigrees around the world, especially of South Asian origin, actually have much more from the Denisovskoy man - a mysterious population of hominids who lived around the same time as the Neanderthals.
A team from Harvard Medical School and the University of California Los Angeles (UCLA) mapped the world and used comparative genomics to predict where Neanderthal and Denisovan genes influenced modern human biology.
The analysis also suggests that modern humans interbred with Denisovan man for 100 generations after they met Neanderthals. The genes of the Denisovan man could potentially be associated with the finer sense of smell of the people of Papua New Guinea and the altitude adaptation of the Tibetans. At the same time, Neanderthal genes found in people around the world are likely to contribute to the coarsening of skin and hair.
Most non-Africans possess at least some of the Neanderthal DNA.
“There are certain classes of genes inherited by modern humans from archaic people with whom they interbred and which may have helped modern humans adapt to their new conditions of residence,” explained senior geneticist David Reich, of the Harvard School of Medicine.
On the other hand, there is a negative selection fact that systematically eliminated origin, which hardly came from modern people.
“We can confirm this elimination for 40,000 years since the appearance of these impurities,” added Reich.
Dr. Reich and laboratory members Swappan Mallick and Nick Patterson have partnered with previous laboratory member Sriram Shankararaman, assistant professor of computer science at the University of California at Los Angeles, during the project. They found evidence that the origins of both Denisovan man and Neanderthal man were lost due to the X chromosome, as well as genes expressed in the male testes. According to the team's theory, this contributed to the decline in male fertility, which is usually seen in other hybrids between two very divergent groups of the same species.
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The researchers gathered their data by comparing the known gene sequences of Neanderthals and Denisovans among more than 250 genomes from 120 non-African populations in a public domain through a project called the Simons Genome Diversity Project.
The analysis was carried out using a learning machine algorithm, which is able to distinguish between the components of two types of hereditary DNA, which are closer to each other than to modern humans. A limitation of the study was that the algorithm relies on the current library of ancient genomes available.
“We cannot use this data to draw conclusions about what Denisovsky and Neanderthals looked like, what they ate, or what kind of diseases they were susceptible to. We are still far from this understanding,”said Shankararaman, the first author of the printed version.
A new map of archaic origin has been published in the journal Current Biology.