Using the new genomic data, the team assembled the largest catalog of Denisovan DNA identified so far.
They used a laboratory method known as a massively parallel reporter assay, which tests how genetic variants influence gene activity.
The findings suggest Denisovan DNA helped ancient populations deal with viruses, bacteria, and other pathogens encountered after entering new environments across the Pacific.
Natural selection appears to have increased the frequency of several Denisovan-derived variants in Near Oceanian populations.
Thousands of Denisovan genetic variants remain active today, particularly in genes involved in immune responses and protection against disease.
Ancient DNA inherited from Denisovans, an extinct group of human relatives, still influences the biology of people living in parts of Oceania today, according to a new study published in Science.
The research provides one of the most detailed pictures yet of genetic diversity across Near Oceania, a region that includes Papua New Guinea, the Bismarck Archipelago, and the Solomon Islands. Scientists say populations from this part of the Pacific have received far less attention in genetic research than populations from Europe and other regions, leaving major gaps in knowledge about human history and health.
To address this problem, researchers led by Yale University sequenced the genomes of 177 people from 12 populations in Near Oceania. They compared those genomes with 1,284 previously published genomes from populations around the world.
The results traced a long and complicated population history stretching back at least 45,000 years. Early modern humans reached the Pacific and encountered Denisovans, an ancient human group known mostly through fossils and DNA evidence. Over time, these populations interbred, leaving Denisovan genetic material in the genomes of their descendants.
Researchers found evidence that the ancestors of Near Oceanian populations mixed with at least three different Denisovan-related groups. Using the new genomic data, the team assembled the largest catalog of Denisovan DNA identified so far. The catalog contains roughly three times more Denisovan-derived sequences than previous datasets. More than 70% of those sequences were found only in Oceanian populations.
Some modern populations in Papua New Guinea carry up to 5% Denisovan ancestry, among the highest levels recorded anywhere. By comparison, people from East Asia typically carry around 0.1%.
The researchers then examined whether these ancient DNA segments still affect human biology. They used a laboratory method known as a massively parallel reporter assay, which tests how genetic variants influence gene activity.
The experiments identified 3,127 Denisovan-derived variants that remain functional in living people. Many of these variants act like genetic switches, increasing or reducing the activity of nearby genes.
A large number were linked to the interferon-gamma signaling pathway, an important part of the immune system’s response to infections. The findings suggest Denisovan DNA helped ancient populations deal with viruses, bacteria, and other pathogens encountered after entering new environments across the Pacific.
Natural selection appears to have increased the frequency of several Denisovan-derived variants in Near Oceanian populations. Some of those variants are associated with immunity, metabolism, fertility, and skeletal development.
One example involves a gene called TRPS1, which plays a role in bone growth and skeletal formation. Researchers identified Denisovan-derived variants in this gene that appear to have been favored over time. Scientists noted that TRPS1 has experienced strong selection in several unrelated populations around the world, including rainforest hunter-gatherers in Central Africa and highland populations in Ecuador.
The study adds to growing evidence that DNA inherited from extinct human groups continues to affect living populations. Thousands of Denisovan genetic variants remain active today, particularly in genes involved in immune responses and protection against disease.
Beyond human evolution, the work highlights the importance of including underrepresented populations in genetic research. A broader picture of human genetic diversity helps scientists better understand population history and provides information that could improve future biomedical research for communities across the Pacific.
