This week, William Goodwin of the University of Glasgow, UK, and colleagues describe DNA from the bones of a Neanderthal infant found in a cave in the northern Caucasus mountains of southern Russia.

This is only the second reported case of Neanderthal DNA. The first, from Munich-based ancient-DNA pioneer Svante PÄÄbo and his colleagues, described DNA extracted from the bones of the first ever Neanderthal to be discovered, the historic 'Feldhofer' Neanderthal, found in Germany in 1856. That benchmark study was published in the journal Cell in 1997. The new data, reported in Nature1, are arguably even more important for two reasons.

The new study vindicates the Cell report. Although researchers agree that the earlier work was first-rate, the study of ancient DNA has been dogged by worries of contamination - especially when that DNA comes from creatures closely related to ourselves. The new data also support the widely held but still contentious view that modern humans had little or no genetic admixture with the Neanderthals.

According to the 'multiregional continuity' model of human origins, modern humans developed in several parts of the world simultaneously, with people in each area having their own regional antecedents. Neanderthals lived in Europe and western Asia from around 230,000 years ago until sometime after 30,000 years ago (indeed, the Caucasus Neanderthal is one of the last known of its kind.)

Modern humans, anatomically distinct from Neanderthals, first appeared in Europe around 40,000 years ago. In the multiregional continuity view, modern Europeans were descendants of indigenous Neanderthals, or at least had considerable genetic admixture: but this would not be true for modern humans evolving in other parts of the world, such as Africa or eastern Asia.

In the competing 'out of Africa' view, modern humans migrated from Africa to other parts of the world around 100,000 years ago and replaced indigenous forms. In this scheme, Neanderthals would have become extinct, leaving no modern descendants anywhere in the world, including Europe.

If the 'mutiregional continuity' view is correct, then Neanderthal DNA should resemble that of modern Europeans more than the DNA of modern Asians or Africans. But the Feldhofer Neanderthal DNA seems to be distinct from the DNA of any modern human, irrespective of racial or geographical origin. The Caucasus Neanderthal DNA now confirms this: it is closer to the Feldhofer DNA than to any modern human. This evidence does not refute the multiregional continuity theory, but neither does it support it.

But the Caucasus DNA and the Feldhofer DNA are quite distinct, having a 3.48% difference in sequence. This is comparable to differences between humans of different ethnic or geographic origins, and is not surprising given that the Feldhofer and Caucausus individuals lived 2,500 kilometres and tens of thousands of years apart (the geological age of the Feldhofer Neanderthal is not known for certain.)

The research is a beacon of hope for studies of our closest extinct relative. Neither the Caucusus nor the Feldhofer remains were preserved in ideal conditions for the retrieval of delicate DNA that is tens of thousands of years old. Unlike Siberian mammoths or the Tyrolean 'iceman', they were not frozen in the permafrost of a glacier. This suggests that more DNA from Neanderthal specimens - even the most ancient remains - might be extracted to give a snapshot of the evolution of a complete species from start to finish.