Complete mitochondrial genome sequence of a Middle Pleistocene cave bear reconstructed from ultrashort DNA fragments

Outside of permafrost, no contiguous DNA sequences have been generated from material older than ∼120,000 y. By improving our ability to sequence very short DNA fragments, we have recovered the mitochondrial genome sequence of a >300,000-y-old cave bear from Sima de los Huesos, a Spanish cave site that is famous for its rich collection of Middle Pleistocene human fossils. This finding demonstrates that DNA can survive for hundreds of thousands of years outside of permafrost and opens the prospect of making more samples from this time period accessible to genetic studies.