A roughly 110,000-year-old Neanderthal male and a roughly 120,000-year-old Neanderthal recovered from the same Siberian cave belong to closely related populations separated by about 10,000 years, according to a new high-coverage genome analysis. The two individuals, known as D17 and D5, were both found at Denisova Cave in the Altai Mountains of southern Siberia. Their genetic similarity across such a long span suggests that small, interconnected Neanderthal groups returned to this remote site generation after generation, maintaining recognizable genetic signatures even as ice ages and other hominin species reshaped the region around them.
Why the D17 and D5 genomes reshape Neanderthal population history
The finding matters because it challenges a simpler story about how archaic humans moved across Eurasia. If unrelated Neanderthal bands had drifted into the Altai independently over tens of thousands of years, the two genomes would show far greater divergence. Instead, D17 and D5 sit within the same regional population cluster, pointing to durable local networks rather than waves of long-distance migration. The practical test is straightforward: if future high-coverage genomes from adjacent Altai sediment layers show similarly low divergence despite multi-millennial gaps, the case for stable, site-specific mating networks would grow stronger, and the alternative explanation of repeated dispersals from distant Neanderthal heartlands in western Eurasia would weaken.
Denisova Cave is already the only known site where three distinct hominin groups left genetic traces: Neanderthals, Denisovans, and at least one individual of mixed ancestry. Sedimentary ancient DNA recovered from stratified deposits at the cave confirms that Neanderthals and Denisovans occupied it at different times across hundreds of thousands of years. Against that backdrop, the D17–D5 comparison adds a new dimension. It is no longer just that multiple species used the cave. Within one species, genetically connected groups kept coming back.
How a 37-fold genome sequence links two Denisova Cave Neanderthals
The core evidence comes from a genome sequenced at approximately 37-fold coverage from the D17 specimen, a Neanderthal male dated to roughly 110,000 years ago. That depth of sequencing, reported in Proceedings of the National Academy of Sciences, allowed researchers to compare D17 in fine detail against D5, a Neanderthal from the same cave dated to roughly 120,000 years ago. The comparison showed the two were not in a direct ancestor–descendant line but belonged to closely related Altai populations. An earlier high-quality Neanderthal reference genome from the Altai region provided the comparative framework that made this level of resolution possible.
The age estimates for both individuals rely on Bayesian models that combine chronometric measurements with stratigraphic information from the cave’s layered sediments. That same modeling approach produced the age estimate for Denisova 11, the famous Neanderthal–Denisovan offspring whose discovery confirmed that the two species interbred at this very site. Earlier mitochondrial DNA work at the cave had already established that multiple mtDNA lineages were present, with time since the most recent common ancestor measured on the order of thousands of years. The D17 genome adds nuclear DNA depth to that mitochondrial picture, sharpening the resolution from broad lineage groupings to population-level relationships.
What the genome does not do is tell us exactly how D17 and D5 were related in a family-tree sense. The data rule out a parent–child or grandparent–grandchild link across the 10,000-year gap, but they confirm the two belonged to populations that exchanged genes regularly enough to remain genetically close. That pattern is consistent with small, semi-isolated groups whose members mated within a limited geographic range, returning to favorable shelters like Denisova Cave across deep time.
Gaps in the fossil record and what comes next for Altai genetics
Several questions remain open. No published osteological or isotopic analysis confirms the biological relationship between D17 and D5 beyond what the genomic comparison reveals. The skeletal fragments from Denisova Cave are generally small and poorly preserved, which limits what traditional physical anthropology can contribute. The stratigraphic layer assignments for both individuals depend on the Bayesian dating models rather than direct radiocarbon measurements, and raw luminescence or radiocarbon data for these specific specimens have not been independently reproduced in the available literature.
Field context is another gap. Direct statements from excavators about the precise recovery positions of D17 and D5 within the cave’s chambers are absent from the published genetic and chronological summaries. Denisova Cave has multiple chambers with complex depositional histories, and a detailed genetic reconstruction of archaic hominins at the site has shown that sediment layers can contain DNA from species that occupied the cave thousands of years apart. That complexity makes it difficult to translate a genetic relationship between two individuals into a clear behavioral scenario about shared camp spaces, hunting territories, or seasonal movements.
Even so, the D17 genome underscores how much information can be extracted from fragmentary remains when combined with stratigraphy and Bayesian modeling. With only a few bones and teeth, researchers can now infer not just species identity but also population structure, degrees of relatedness, and broad patterns of movement across landscapes. For the Altai, that means shifting from a picture of sporadic Neanderthal incursions into a Denisovan stronghold to one in which Neanderthal groups had a longer, more continuous presence than their sparse fossils alone would suggest.
Future work will depend on expanding both the genetic and environmental records. Additional high-coverage genomes from Denisova Cave and neighboring sites could test whether the D17–D5 relationship is representative of a long-lived local population or a chance pairing within a more fluid metapopulation. Parallel studies of animal bones, plant remains, and microstratigraphy could clarify whether climatic or ecological changes align with shifts in the genetic makeup of cave occupants. If, for example, a cooling phase coincided with the disappearance of one Neanderthal lineage and the appearance of another, that would support a model of climate-driven population turnover rather than simple continuity.
At the same time, the Altai data must be integrated with Neanderthal genomes from western Eurasia to understand how local continuity in Siberia fits into the species’ broader history. If Altai Neanderthals remained genetically cohesive over tens of thousands of years while western groups show more rapid turnover, that contrast could reflect differences in habitat stability, population density, or contact with other hominins. Conversely, if similar patterns of long-term regional continuity emerge elsewhere, the species as a whole may have been more rooted and less nomadic than once assumed.
For now, D17 and D5 offer a rare, time-separated snapshot of related Neanderthal populations using the same shelter in the deep past. Their genomes bridge a 10,000-year gap and hint at social worlds that left almost no visible trace in the cave sediments. As more ancient DNA emerges from Denisova and beyond, those faint genetic echoes may be the best guide to how Neanderthals organized their lives at the edge of the Ice Age world.
More from Morning Overview
*This article was researched with the help of AI, with human editors creating the final content.
