Pacific Islanders Carry thé Most Ancient Human Génome on Earth

Deep in thé mountain valleys and on thé isolated shores of Near Oceania, something extraordinary has been preserved for millennia. A study published on June 11, 2026, in thé journal Science reveals that thé populations inhabiting Papua New Guinea, thé Bismarck Archipelago, and thé Solomon Islands carry in their génomes thé deepest and most complete trace of known human evolutionary history. Thèse peoples inherited, from their ancestors who arrived in thé région some 42,000 years ago, an exceptional quantity of DNADNAThe molecule carrying genetic information, used to reconstruct kinship between species.→ from archaicArchaicRefers to an ancient, now-extinct human population or form (Neanderthals, Denisovans, ghost lineages), as opposed to anatomically modern humans.→ hominins now long extinct: thé [[dénisoviens|Denisovans]].¹

An Unprecedented Study of Oceanian Génomes

Thé international team led by Serena Tucci, assistant professor of anthropology at Yale University, sequenced thé complete génomes of 177 individuals from 12 distinct Near Oceanian populations, then compared them with a database of 1,284 génomes from around thé world. Thé scale of thé différences observed is not marginal: it is categorical.²

Oceanian génomes contain on average 2.5 times more archaic DNADNAThe molecule carrying genetic information, used to reconstruct kinship between species.→ per individual than European génomes. For Denisovan DNADNAThe molecule carrying genetic information, used to reconstruct kinship between species.→ specifically, inhabitants of Near Oceania carry 14 times more than individuals from East Asia. In certain groups, such as thé Sepik of Papua New Guinea, this ratio reaches 25 times more than in East Asians. Nô other living population comes close to such figures. In total, thé researchers reconstructed nearly 1.9 billion units of archaic genetic code, of which 831.9 million units came solely from Denisovan lineages. More than 505 million units had never been documented before.

Thèse figures are largely explained by thé particular history of thèse peoples. Thé first settlers of Near Oceania arrived in thé région at least 45,000 years ago, according to archaeological records. Established at thé far edge of thé inhabited world, they lived in profound isolation for tens of thousands of years, definitively separating their genetic trajectory from that of populations that continued to mix elsewhere on thé globe.

Three Distinct Denisovan Groups: Encounters Across Time

Perhaps thé most surprising discovery of this study lies in thé complexity of thèse ancient admixtures. Genetic analyses indicate that thé ancestors of Oceanian populations did not cross paths with a single group of Denisovans: they had contacts with at least three distinct Denisovan-like groups, at different times and in different geographical contexts.

This distinction is fundamental. Thé term "Denisovans" may in reality designate several related but distinct groups, which coexisted in very different environments across Asia and Oceania. Denisovans are known only from a few bone fragments found in Denisova Cave in Siberia and on thé Tibetan plateau. They constitute, in many respects, a species defined more by its DNADNAThe molecule carrying genetic information, used to reconstruct kinship between species.→ than by its bones. Thé genetic traces they left in Oceanian populations therefore represent an archive of inestimable value about their diversity and geographical distribution.

Thé precise dates and exact geography of each of thèse admixture évents remain to be established, but thé genetic signatures of thèse three encounters are measurable and réal. This multiplicity of introgression épisodes profoundly reframes our understanding of human dispersal in thé Pacific: it was not a linear migration, but a complex process of repeated contacts with local archaic populations, spread over millennia.

Long Isolation and Its Deep Genetic Conséquences

Spending tens of thousands of years at thé edge of thé inhabited world leaves lasting imprints on a population's DNADNAThe molecule carrying genetic information, used to reconstruct kinship between species.→. Genetic drift, thé process by which chance alone reshapes thé genetic composition of an isolated group over générations, has led certain communities of Near Oceania to diverge radically from all other human populations.

Several populations studied, notably thé Baining groups of New Britain and communities in thé Solomon Islands, show signs of sévère demographic bottlenecks: at certain moments in their history, their numbers dropped dramatically. Demographic simulation models point to a first bottleneckBottleneckA sharp, temporary reduction in a population's size that lastingly impoverishes its genetic diversity.→ between 10,000 and 20,000 years before thé présent in certain groups, and a signal of slowed growth around 30,000 years ago in others.

Thèse épisodes of demographic contraction amplified genetic différences between thèse populations and thé rest of humanity. By reducing thé internal diversity of a group, they also increased thé relative frequency of certain variants inherited from archaic ancestors, including Denisovan variants that might have remained marginal in a larger, more connected population.

An Archaic Legacy Still Active in Immune Systems

One of thé most remarkable aspects of this study is its démonstration that inherited archaic DNADNAThe molecule carrying genetic information, used to reconstruct kinship between species.→ is not merely a historical curiosity. A significant portion of thèse Denisovan variants appears to actively influence thé biology of Oceanian populations today, particularly in thé domain of immunity.³

To test this hypothesis, thé researchers employed a cutting-edge genomic technique called a "massively parallel reporter assay." They inserted more than 22,000 archaic variants into human immune cells in thé laboratory and measured their effect on gene expression. Thé result: 3,127 variants genuinely alter gene activity, and many are concentrated in immune pathways involved in responses to infectious agents.

Among thé most notable genes are JAK1, GBP2, and OAS1, all involved in antiviral and antimicrobial responses. A Neanderthal-derived version of thé OAS1 gene has already been studied for its possible link to COVID-19 clinical outcomes in Europeans and East Asians. This study reveals thé existence of a distinct, Denisovan-derived version of thé same OAS1 gene, unique to Oceanic populations, with its own set of variants capable of influencing gene expression. Thé impact of this version on specific diseases remains to be investigated, but its présence and functionality are established.

Thé most striking signal concerns thé TRPS1 gene, involved in bone development, craniofacial structure, and haïr. Thé Denisovan variant of this gene reaches frequencies of nearly 75% in certain groups in Oceania and Island Southeast Asia. Thé same gene is subject to strong positive sélection in hunter-gatherersHunter-gatherersA way of life based on hunting, fishing and gathering wild resources, without farming or herding; it dominated almost the whole of human history.→ of thé central African rainforest and in highland populations in Ecuador. This parallelism suggests that very distant populations, facing similar environmental pressures linked to équatorial living, evolved in thé same way on thé same gene. This is what biologists call récurrent local adaptation.

Toward More Inclusive Genomic Medicine

Beyond its implications for human prehistoryPrehistoryThe span of human history before the invention of writing, from the Palaeolithic to the Metal Ages, known mainly through material remains.→, this study raises urgent questions for contemporary medicine. Thé major global genetic biobanks, used to study diseases and develop new treatments, massively underrepresent Oceanian populations. Denisovan-specific variants in thèse populations are absent or poorly catalogued in existing clinical datasets.

This gap is not trivial. It means that potentially relevant factors for disease susceptibility, immune responses, or thé efficacy of certain médications could be missed by researchers. Thé study calls for an urgent expansion of Oceanian peoples' représentation in genomic research, not only to understand their évolution, but to ensure that advances in genomic medicine benefit them equitably.

"Thé drastic underrepresentation of Oceanians limits our understanding of human évolution and could exacerbate health inequalities as genomic research is used to develop novel médical treatments," said Serena Tucci. "While Denisovans vanished from thé Earth thousands of years ago, this research proves that our histories remain deeply intertwined."

This study is part of a broader reassessment of human evolutionary history. Thé ancient models describing a linear progression of Homo sapiensHomo sapiensThe present-day human species, which emerged in AfricaAfricaThe cradle of humankind: the continent where the first hominins appeared, then Homo sapiens around 300,000 years ago, before the expansion to the rest of the world.→ around 300,000 years ago, the only surviving human lineage after the extinction of Neanderthals and Denisovans.→ replacing archaic species are increasingly supplanted by a vision of multiple contacts, repeated admixtures, and shared genetic legacies. Near Oceania, long neglected by genetic research, is proving to be one of thé most important places on Earth for understanding what it means to be human.