An international team of researchers has determined from DNA that in addition to Neanderthal and modern man a third species of humans, dubbed Denisovans, lived in Siberia as recently as 30,000 years ago. A draft genome sequence revealed the species to be a sister group of Neanderthal and that a significant amount of the DNA (about 5%) exists in at least some modern day Melanesians.
Per the article:
"The Denisovans appear to have been quite different both genetically and morphologically from Neanderthals and modern humans. The tooth found in the same cave as the finger bone shows a morphology that is distinct from Neanderthals and modern humans and resembles much older human ancestors, such as Homo habilis and Homo erectus. DNA analysis showed that the tooth and the finger bone came from different individuals in the same population."
The findings have been published in the 12-23-10 issue of the journal, Nature.