The “dense” genetic ratio of the human species among the inhabitants of this island nation has been preserved through 50,000 years of genetic isolation.
According to a study recently published in Nature Communications, genes from the ancient Denisovans have enabled the people of Papua New Guinea to possess superior resistance to certain diseases and adapt to environments that could suffocate ordinary individuals.
Papua New Guinea is an island nation located in Oceania, situated on an island off the coast of the Pacific Ocean.
The people of Papua New Guinea inherit certain advantages in immunity and adaptation to high altitudes thanks to the genes of ancient Denisovans – (Photo: SHUTTERSTOCK).
“The people of Papua New Guinea are unique because they have been isolated since settling here over 50,000 years ago,” said co-author François-Xavier Ricaut, a biological anthropologist at the French National Centre for Scientific Research (CNRS), to Live Science.
Dr. Ricaut and colleagues analyzed the genomes of 54 individuals from Mount Wilhelm, living at altitudes of 2,300 – 2,700 meters above sea level, and 74 individuals from Daru Island, living below 100 meters above sea level.
They discovered that mutations likely inherited from Denisovans have increased the number of immune cells in the blood of lowland inhabitants.
For example, Denisovan gene variants may affect the function of a protein called GBP2, which helps the body combat common pathogens found in lowland areas, such as malaria parasites.
The research team noted that these genes may have been selected during the evolutionary process.
This is particularly significant in this isolated island nation, where infectious diseases account for up to 40% of deaths in the community.
Meanwhile, highland residents have evolved mutations that increase red blood cell counts, helping to alleviate oxygen deprivation at altitudes where ordinary people often struggle to breathe.
In fact, people in many other countries, especially in Asian nations including our own, also carry Denisovan genes in their bodies.
However, the rate of these alien genes among the people of Papua New Guinea is extremely high, reaching up to 5%. Most people in other countries carry Neanderthal or Denisovan genes at about 2% or lower.
Previous studies have shown that Homo sapiens – our species – migrated from Africa to this island region around 50,000 years ago. This could have been the time they encountered and interbred with the Denisovan community here, preserving that bloodline due to limited interaction with other communities around the world.
The Denisovans, like the Neanderthals, are among the closest ancient humans to Homo sapiens. Therefore, these species could interbreed in various places around the world.
Both of these hybrid ancestor species became extinct over 30,000 years ago.
