The DNA of the Denisovansour extinct prehistoric cousins, still surprises the scientific community for its persistent influence on modern humans, particularly among Inhabitants of Papua New Guinea. These people, whose genetic history remained largely isolated for millennia, possess unique genetic characteristics that allowed them to adapt and survive in one of the most challenging environments on Earth.
According to a recent study published in the journal Nature Communicationsthese inhabitants have up to a 5% Denisovan DNA in their genomes, a significantly high percentage that demonstrates the deep imprint that distant ancestors left on human DNA.
This research demonstrates how different genetic mutations prepared the mountaineers and the lowlanders of Papua New Guinea to confront their respective environments. Mutations in lowland inhabitants increase the number of immune cells in the bloodwhich contributes to its resistance against infections.
François-Xavier Ricautco-lead author of the study and biological anthropologist at the French National Center for Scientific Research (CNRS), describes Papua New Guinea as a “fantastic cocktail” to study genetic adaptationgiven its mostly mountainous topography and the high rates of infectious diseases that together represent a considerable challenge for its inhabitants.
“The people of New Guinea are unique because They have been isolated since they settled there more than 50,000 years ago“added the French biological anthropologist, in an interview with Live Science.
The focus of the study was aimed at differentiating the consequences between mountain dwellers and those at sea level. The people analyzed, for height, are from Mount Wilhelm (between 2,300 and 2,700 meters above sea level) and there were 54 in total. Regarding the lowlands, 74 inhabitants were taken from the daru island.
“The selected genetic variants identified in our study show associations with blood-related phenotypes“, he said Mathilde Andrélead author of the Institute of Genomics, to Phys. The inhabitants of Mount Wilhelm showed implications in the percentage of Red blood cells in blood, while those on Daru Island had modifications with respect to the white blood cells.
The study showed that certain specific pathogens influenced genomic evolution in the lowlands. Curiously, some of the Selected lowland genes appear to have non-human originwhich makes it clear how the interaction between different hominid species shaped their evolution in ways still visible today.
“It appears that the altered protein is beneficial for lowlanders to survive in their environment. Although we do not know the exact cause of this selection, this mutation could help lowlanders overcome malaria“, he clarified Mayukh Mondal, from the Genomics Institute, which co-directed the project.
This genetic intertwining with the Denisovans sheds light the human ability to adapt to extreme conditions. It also suggests that genetic mixing between different hominid species may have been more common and biologically significant than previously thought.
As for the inhabitants of Mount Wilhelm, they developed genetic variants that increase your red blood cell counta crucial adaptation for survive reduced oxygen availability at high altitudes.
André supports the idea that hypoxia was a key selection factor for the highlanders. While Dr. Nicolas Brucatoco-author from the University of Toulouse, added: “Interestingly, both variants also affect heart rate of individuals with those mutations. This multiplicity highlights the complexity of interpreting the role of genetic mutations. “One mutation can affect multiple phenotypes altogether.”
