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The mysterious Denisovans were only formally identified a decade ago, when a single finger bone unearthed from a cave in Siberia revealed to scientists the ancient existence of a sort of archaic hominin. that we had never seen before.
But that’s only one side of the story. The truth is that modern humans had actually encountered Denisovans long before that. We ran into them ages ago.
So far, in fact, that we have completely forgotten them. Especially since they – and other archaic humans, such as Neanderthals – vanished into the lifeless past, and homo sapiens assumed sole human domination over the world.
But even that is a little questionable.
All of these varieties of hominids tended to interbreed with each other when they coexisted, which is why, in a way, ancient humans still live in our modern human DNA.
Now, a new study reveals where the imprint of this genetic fingerprint can be most clearly identified today.
According to the study, led by the first author and geneticist of human evolution Maximilian Larena of Uppsala University in Sweden, a Filipino Negrito ethnic group called Ayta Magbukon today has the highest level of Denisovan ancestry in Sweden. world.
“With the recent description H. luzonensis, we suggest that there were several archaic species that inhabited the Philippines before the arrival of modern humans and that these archaic groups may have been genetically linked, ”the researchers explain in their study.
“Overall, our findings unveil a complex, interwoven history of modern and archaic humans in the Asia-Pacific region, where distinct Denisovan island populations have mixed differently with incoming Australasians in multiple locations and at various times.”
According to the results of the analysis – based on a comparison of about 2.3 million genotypes from 118 ethnic groups in the Philippines – the ancestry level of Denisovan from Ayta Magbukon is about 30 to 40 percent higher than that of the Papuans.
Photos of self-identified Negritos from across the Philippines. (Ophélie Persson)
This is the case, even though the Philippine Negritos subsequently “diluted” the amount of Denisovan genetics from their gene pool, with a more recent mix of East Asian lines, which carry lower amounts of Denisovan lines. Denisovan.
If this dilution effect is taken into account, Ayta Magbukon’s Denisovan ancestry level is up to 46% higher than that of Australians and Papuans, the researchers suggest.
Even without this manipulation, however, evidence suggests that the Ayta Magbukon mixed less with the late arrivals than other Filipino Negrito groups: preserving traces of very old lineages from an archaic source – a fate, for a very long time, to to be forgotten.
The research team worked with volunteers and indigenous cultural communities who participated in this study, and the project was recognized and implemented in partnership with the National Commission for Culture and the Arts (NCCA) of the Philippines.
“Some groups, like Ayta Magbukon, did not cross paths with people who then migrated to the islands,” says population geneticist Mattias Jakobsson, also from Uppsala University.
“This is the reason why the Ayta Magbukons have retained most of their Denisovan genes and therefore have the highest levels of these genes in the world.”
The results are reported in Current biology.
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