Unlocking 22,000-Year-Old Nuclear DNA From Cave Sediment Without Human Skeletons
Scientists have extracted ancient human nuclear DNA from sediment in El Mirón Cave in Spain, recovering genetic material from individuals who lived roughly 22,000 years ago without relying on any physical human remains. The small sediment sample weighed no more than a few grains of rice and required sequencing 100 times to yield usable data after researchers sifted through more than a billion DNA fragments while accounting for modern contamination.
The genetic information likely originated from skin, hair, or blood shed by ancient humans sheltering in the cave. This sedimentary DNA, or sedaDNA, provides nuclear data inherited from both parents rather than just maternal lines, offering a more complete look at lineage.
Connecting Western European Lineages Across the Ice Age
Analysis of the nuclear DNA from El Mirón indicates that its inhabitants belonged to a western ancestry group characterized by dark skin, hair, and eyes. The sample contained a mix of individuals, with more men than women among them. Pere Gelabert and colleagues at the University of Vienna compared these findings against genomic data from an ancient woman in France who lived about 31,000 years ago and a tooth from northern Spain dating to about 25,000 years ago.
Cave dirt in Spain still holds DNA from people who lived 22,000 years ago.Sediment from El Miron Cave yielded about 14,000 human genetic markers with no bones at all, showing a local ancestry survived the peak of the last Ice Age in southwest Europe (Science Advances).
Those older samples revealed signs of eastern ancestry, pointing to interbreeding between human populations at opposite ends of Europe before the last glacial maximum. By contrast, the 22,000-year-old DNA from El Mirón displayed only signs of western ancestry. According to the study published in Science Advances, this genomic evidence argues against a major population replacement or discontinuity in southwestern Europe between 30,000 and 20,000 years ago.
Expanding Genetic Mapping Through Isturitz Cave and Sedimentary Sampling
The research builds on broader genetic mapping across Western Europe during the Gravettian culture, which spanned roughly 34,000 to 25,000 years ago. Paleogeneticists sequenced genomes from three Gravettian individuals, including a woman from Isturitz Cave in southwestern France near the Spanish border. This individual provided the oldest complete genome discovered in the region to date. While most of her genome matched western European lineages, she also carried genes originating from central and eastern Europe.
Genetic modeling estimated a pulse of gene flow from east to west occurring between 32,500 and 31,500 years ago. This evidence supports the archaeological theory that Isturitz Cave served as a critical cultural and biological hub situated along a passage between continental Europe and the Iberian Peninsula. Similar genetic patterns appeared in samples from Ormesson, France, and Belgium, broadening the documented scope of long-distance interaction.
Sedimentary DNA techniques are changing how archaeologists approach prehistoric sites where bones are absent. In 2025, researchers discovered animal and human mitochondrial DNA in dirt samples at El Mirón that were dated between 46,000 and 21,000 years ago.
SedaDNA is positioned to reshape research into human dispersal, mobility, and diet. Yet technical hurdles remain. Contamination risks and complex mixtures of environmental DNA continue to complicate analysis, requiring rigorous sequencing protocols.
Resolving the Upper Paleolithic Genetic Landscape
Integrating additional skeletal genomes with expanding sedaDNA datasets remains necessary to fully resolve the population dynamics of Upper Paleolithic Europe. Questions persist regarding the exact migration routes and source populations that drove pulses of gene flow across the continent before the Last Glacial Maximum.
