The Dec. 23rd issue of the journal Nature made a remarkable scientific discovery public this week when they announced a revolutionary revision in human evolution - the existence of a new branch of humanity called the Denisovans. The evidence for this epochal anthropological discovery comes from a cache of bones and stone tools and body ornaments found in a cave in southern Siberia. A 30,000-year-old bone fragment was subjected to DNA analysis and geneticists were stunned when the results came back that it was neither Neanderthal nor modern human, but a genetically distinct third branch of mankind.
Bone Fragment From the Fingertip of a Young Girl
It turned out the bone fragment was from the tip of the little finger of a young Denisovan girl, almost certainly no more than five or six years old. The genetic analysis showed that it was bone material from a previously unknown subgroup of humans. This new group descends from the same Neanderthal group who had branched off earlier than the ancestors of modern humans, but is genetically distinct from other known Neanderthal fossils found in Europe and Asia.
Artifacts and Fossils Recovered in Denisova Cave in Siberia
Aside from the bone fragment, a molar from another Denisovan was also recovered in the cave. This molar was from another (probably adult) individual, but was definitely of Denisovan origin. Cultural artifacts including stone microblades and polished stone ornaments were also recovered by anthropologists from Denisova cave in late 2008.
The Melanesian Connection
One of the most fascinating discoveries related to the Denisovans is their genetic connection to modern Melanesian populations. The DNA analysis found that genetic material from this subgroup of Neanderthals matched 4 to 6 percent of the genes of some extant Melanesian populations. This means that interbreeding took place between Denisovans and the ancestors of Melanesians at some point in prehistory, similarly to the interbreeding that almost certainly took place between modern humans and European Neanderthal populations.
Rewriting Mid-Late Human Evolution and the History of the Neanderthals
The discovery of the Denisovans rewrites the commonly accepted history of Neanderthal man, which has been one of the tenets of modern physical anthropology. According to researchers from the international team investigating the find, the genetic evidence suggests that a protohuman (pre-Neanderthal) ancestral group migrated from Africa around 300,000 or 400,000 years ago and then split relatively quickly, with one branch developing into the European Neanderthals and the other branch traveling east over many generations and becoming the Denisovans.
The Arrival of Modern Humans
Most prehistorians believe the most recent step in the evolution of modern humans was several waves of migration from Africa around 75,000 years ago. These groups almost immediately encountered and interbred with Neanderthal populations, as remnants of Neanderthal DNA make up 1 to 4 percent of the genes of all modern non-African human populations. Physical anthropologists theorize that at least one other population of modern humans came in contact with Denisovan groups during the many millennia of their migrations (with the descendants of one of these groups becoming modern Melanesians).
Source
Choi, Charles Q. "Finger Bone Points to New Branch of Humanity." Live Science: Yahoo News. Accessed Jan 2011.
Clayton Browne - Clayton Browne has a BA and an MS in Anthropology, and has been writing professionally since 1994. He worked for many years in both ...
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