No Bones Needed: Cave Sediment from 22,000 Years Ago Rewrites Ice Age Population History

Human bones are the scarcest evidence in the study of Ice Age Europe. Around the Last Glacial Maximum (LGM, roughly 26,500 to 19,000 years ago) populations were thin and burials were rare; across the whole Upper Palaeolithic, fewer than fifty individuals in all of Europe have yielded genome-wide data. That shortage is why researchers have turned to an unlikely archive: the dirt on cave floors. On 23 October 2026, Science Advances published a study that recovered enough human nuclear DNA from a sediment layer roughly 22,000 years old at El Mirón Cave in Cantabria, Spain, to assign a genetic ancestry — and, alongside it, genome-wide data from three Gravettian individuals in France, Spain and Italy.

The paper is led by Pere Gelabert of the Department of Evolutionary Anthropology at the University of Vienna, with Ron Pinhasi as senior author, and draws on collaborators from the University of Cantabria, the University of New Mexico, several French and Italian archaeological institutions and David Reich’s group at Harvard Medical School. The question at its centre is an old one. The Gravettian culture (about 34,000 to 25,000 years ago) spread across Europe, and its stone tools, art and burial practices show clear similarities from east to west. Genetic data, however, had suggested that eastern and western populations remained largely separate, aligned with two distinct ancestry strands known as Fournol and Véstonice. With so few skeletons, that contradiction could not be tested at finer temporal resolution.

Three new skeletons help close the gap. A woman from Isturitz Cave in the French Basque Country, dated to 26,030 ± 220 years ago, provides the oldest genome-wide dataset yet obtained from a modern human in southwestern Europe. An individual from Chufín Cave in Cantabria, 22,793 ± 116 years ago, anchors a later Gravettian presence in that region. And Ostuni1b, a male fetus from a cave in southern Italy, is the son of the previously studied woman Ostuni1, offering a direct look at family structure within a south-central European Gravettian group.

The sediment work targeted Layer 122 at El Mirón, a Solutrean deposit radiocarbon dated to 22,100–21,730 cal BP, near the end of the cave’s human occupation. From two extracts the team built nine libraries and sequenced each about ten times — 68 runs after in-solution enrichment with the TWIST 1.4M human nuclear capture kit and 33 shotgun runs — producing just over one billion sequences. From these they recovered 294,109 unique human reads covering 51,081 positions on the 1240k panel; after damage restriction and read trimming, 14,737 single-nucleotide polymorphisms remained for analysis. That was enough, in the complete absence of bones or teeth, to tie an archaeological layer to a specific genetic ancestry. Coverage on the autosomes and the X chromosome was similar, suggesting the human DNA came from more males than females.

The first major finding is gene flow between east and west that earlier data had missed. The Isturitz woman’s ancestry is mostly western European, but she also carries a component linked to central and eastern European populations. Modelling places that exchange at roughly 32,500 to 31,500 years ago, and a previously published individual from Ormesson in France shows a comparable signal. The result undercuts the long-standing model of genetic continuity from the Aurignacian to the Solutrean in southwestern Europe. Given Isturitz’s exceptionally rich archaeological record, the site may have served as a gathering place for different groups.

The second finding is long-term continuity in the southwest. Chufín supplies a temporal anchor at about 26,000 years ago, showing that once Gravettian populations had mixed, the region’s genetic structure stayed stable for millennia. The El Mirón sediment then extends Fournol-related ancestry directly to the final Solutrean, around 22,000 years ago. In other words, the Iberian Peninsula’s role as an LGM refugium holds up genetically: populations contracted into the southwest without being wholesale replaced.

The third finding comes from the Italian mother and child. Ostuni1b’s father most likely belonged to the same genetic population as his mother, yet the parents were not closely related — evidence, the authors argue, of mating arrangements that helped avoid high levels of inbreeding. That runs against the intuition that small, isolated groups must become inbred, and shows that regional continuity can coexist with exchange across vast distances.

The methodological point may matter more than any single result. Sedimentary DNA (sedaDNA) had previously been used at El Mirón mainly for mitochondrial work, which tracks only the maternal line. With nuclear capture and deep sequencing, an environmental sample now yields enough to place ancestry genome-wide. For periods when bones are almost absent — the LGM above all — this means continuous stratigraphic sequences can be used to watch populations replace, mix and persist, without waiting for a skeleton that happened to survive. The team’s next step is to combine sedaDNA with palaeoproteomics, to reach fragments that cannot be identified morphologically but still carry molecular information.

The limitations are equally clear. Sediment DNA is a mixture from multiple individuals, low in coverage and heavy in damage, and far fewer positions can be called confidently than from bone. Three skeletons plus one sediment layer cannot represent Europe. But the work moves Late Palaeolithic population history from broad outlines supported by a handful of skeletons toward models testable at the scale of a single layer and a single millennium: the Gravettian groups of east and west were neither isolated islands nor a uniform mass, but a network of long-distance contact layered over regional continuity.

The entrance of El Mirón Cave in Cantabria, Spain; the sedimentary DNA analysed in this study comes from the Solutrean layer in the cave’s rear vestibule. (Image: New Scientist report, photograph by Lawrence Guy Straus)