A paper in Cell is reporting the sequence of a Neanderthal mitochondrial DNA genome. Mitochondrial DNA, which you inherit only from your mother, has long been among the most useful DNA regions for tracing your ancestry. In the Neanderthal mitochondrial genome, researchers found, not surprisingly, that the sequence differences are well beyond the range of what we see within human populations, meaning that Neanderthals clearly were a distinct biological sub-species. The researchers also found that this sequence suggested we split off from Neanderthals about 660,000 years ago (give or take 140,000 years). This is not my specialty, but I believe this fits reasonably well with existing ideas about human speciation, particularly with the fact that humans in their modern form start appearing in the archeological record between 100,000 and 200,000 years ago. This leaves plenty of time for humans and Neanderthals to diverge genetically.