Serena Tucci still remembers the moment her team identified a Denisovan genetic variant in a Papua New Guinean participant that was actively regulating a gene tied to immune response — a ghost from humanity’s ancient past, still shaping lives today. Her Yale-led study, published June 11 in Science, has uncovered how DNA inherited from Denisovans, an extinct human relative, continues to influence the biology of modern Oceanian populations, particularly in immunity and skeletal development. By sequencing the genomes of 177 individuals from 12 populations across Near Oceania — including Papua New Guinea, the Bismarck Archipelago, and the Solomon Islands — and combining them with 1,284 global genomes, Tucci and her team have filled a critical gap in human genomics, one long skewed by the overrepresentation of European ancestry in genetic research.
The implications are profound. For decades, scientists knew that fragments of Neanderthal and Denisovan DNA lingered in modern humans, remnants of ancient interbreeding. But this study moves beyond mere detection, demonstrating that these archaic sequences are not silent fossils — they’re functional, dynamic regulators of gene expression. Using a cutting-edge technique called a massively parallel reporter assay, the researchers tested how inherited variants affect gene activity, identifying over 3,100 that alter gene expression. Most strikingly, many of these active variants are linked to the interferon-gamma signaling pathway, a cornerstone of the immune system’s defense against viruses and bacteria.
"DNA from extinct hominins — Denisovans and Neanderthals — helped facilitate human adaptation to diverse environments that people encountered as they migrated into this region of the world," said Patrick Reilly, the study’s first author. Pathogens, he notes, have been one of the strongest evolutionary pressures in human history, and the Denisovan variants appear to have given early settlers of Near Oceania a survival edge. The study also uncovered adaptive Denisovan variants in the TRPS1 gene, which influences skeletal development. This same gene has undergone strong selection in Central African rainforest hunter-gatherers and Ecuadorian highlanders, suggesting convergent evolution across vastly different environments.
This research does more than rewrite chapters of human evolution — it underscores the urgency of inclusive genomics. As medical advances increasingly rely on genetic data, the historical exclusion of Oceanian populations risks widening global health disparities. But here, in the living genomes of Near Oceanians, lies a powerful testament to resilience and adaptation. "While Denisovans vanished from the Earth thousands of years ago, this research proves that our histories remain deeply intertwined," Tucci said. Their legacy isn’t buried in Siberian caves — it pulses in the blood and bones of people today, a quiet, enduring force in the story of human survival.