Ethnic group in the Philippines has the highest level of Denisovan DNA in the world

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A to study analysis of the genomes of nearly 120 ethnic groups in the Philippines has identified that one population, the Ayta Magbukon, has the highest level of DNA derived from Denisovan, an extinct human subspecies, recorded to date .

The Denisovans, unlike the better-studied Neanderthals, were only discovered by modern science a decade ago, when mysterious remains found in a cave in Siberia turned out to be of a previously unidentified subspecies.

From Siberia to Southeast Asia


Since this discovery, scientists have only found Denisovan’s DNA at another location, the Baishiya Karst cave site on the Tibetan Plateau. Computer analysis using the genome found in Siberia has enabled researchers to quantify the contribution of Denisovan DNA to the genomes of modern humans. Previous research had identified Australasians have the highest level of Denisovan DNA compared to any other population.

But the Australasian population covers a large area of ​​Insular Southeast Asia (ISEA), including the complex ethnic melting pot of the Philippines. Here, over 100 distinct ethnic groups to occupy 2000 inhabited islands. In the new study, a team of Filipino and international researchers examined the DNA of 1,107 individuals from 118 ethnic groups with 2.3 million different genetic variations.

Who are the Filipino negritos?

Filipino negritos are believed to be the
earlier human population to have migrated to the Philippines. At least 30 self-identified Negrito groups speak different Malayo-Polynesian languages. The researchers noted that the 25 groups contacted in this study were split between hunting and gathering, subsistence and urbanized lifestyles, with many of their languages ​​considered critically endangered.



The in-depth analysis showed that the genome of Ayta Magbukon Negrito contains the highest proportion of Denisovan DNA. The Ayta Magbukon population, which the authors say has not been the subject of any genomic study before, occupies Bataan province in central Luzon. It has been proven that many populations of Negrito have previously mixed with populations from East Asia, which have much less genetic contribution from Denisovans in their genome. Using a genomic tool called masking, researchers, including one at Uppsala University Maximilian Larena, were able to identify significant differences in genomic contribution. “If we account for and mask the East Asian ancestry of the Filipino Negritos, their Denisovan ancestry can be up to 46% higher than that of Australians and Papuans,” Larena said, in a report. Press release.

A complex story


The results surprised the team. Previous studies suggested that a relatively simple one-time mixing event had occurred between Australasians and Denisovans, but these new findings imply that multiple mixing events occurred in different places and at different times. “In [ISEA], Philippine Negritos then mingled with East Asian migrants who have little Denisovan ancestry, which subsequently diluted their archaic ancestry. Some groups, however, such as the Ayta Magbukon, have mixed little with the more recent inbound migrants. For this reason, the Ayta Magbukon kept most of their inherited archaic tracts and ended up with the highest level of Denisovan ancestry in the world, ”the authors explain in the publication.

The new findings combine with the recent discovery of the remains of another previously unidentified extinct human species, Homo luzonensis, in Luzon, the largest island in the Philippines. Together, the authors suggest that there is a rich tapestry of ancient human interactions to be discovered in ISEA. Putting together this picture could reveal secrets of the entire human race. “By sequencing more genomes in the future, we will have a better resolution to answer multiple questions, including how archaic inherited extents have influenced our biology and how they have contributed to our adaptation as a species,” concluded Larena.

Reference:

Larena M, McKenna J, Sanchez-Quinto F, et al. Philippine Ayta has the highest level of Denisovan ancestry in the world. Current biology. 2021; 31: 1-12. do I:10.1016 / j.cub.2021.07.022


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