Yale-led Science study shows Denisovan variants regulate interferon-gamma pathway in 177 Oceanian genomes

Researchers sequenced 177 individuals from 12 populations across Papua New Guinea, the Bismarck Archipelago, and the Solomon Islands, then merged these with 1,284 published global genomes. They applied a massively parallel reporter assay to test >3,100 archaic variants for effects on gene expression, identifying Denisovan haplotypes that modulate immune loci. This design directly links ancient admixture to present-day regulatory function rather than relying on statistical enrichment alone.

The functional data reveal that Denisovan segments boost or dampen interferon-gamma pathway activity, providing a mechanistic explanation for observed differences in viral and bacterial resistance among Oceanian groups. These variants are absent or at low frequency in European and East Asian reference panels, underscoring how Eurocentric GWAS cohorts have missed adaptive archaic contributions. The work reframes Denisovan introgression as an ongoing immunological resource rather than evolutionary debris.

Key limitation is the modest sample size per population and reliance on in-vitro reporter assays; replication in primary immune cells from the same donors plus longitudinal infection cohorts would strengthen causal claims. Inclusion of these variants in polygenic scores for Oceanian ancestries could narrow health-disparity gaps in vaccine response and sepsis outcomes.

Future studies should test whether the same Denisovan regulatory architecture influences autoimmune risk in admixed Pacific populations, a prediction testable within existing biobanks.