Using novel techniques to extract and study ancient DNA, researchers at the Max Planck Institute in Germany, have sequenced the mitochondrial genome of a 400,000 year old hominin from Sima de los Huesos, a unique cave site in Northern Spain. They found that this group has mitochondrial DNA that is similar to that of the Denisovans, an extinct archaic group from Asia from about 700,000 years ago. The fact that the Sima hominin share a common ancestor with Denisovan rather than Neanderthals is totally unexpected since the skeletal remains at the site display Neanderthal-like features. One possible explanation may be that the Sima hominins are related to a population that is ancestral to both Neanderthals and Denisovans.