According to an article in Nature dated 22 October 2014 the oldest known human genome ever sequenced shows that modern humans (Homo sapiens) roamed across Asia. The DNA came from a 45,000 year old leg bone found in Siberia known as the Ust’-Ishim Femur bone. What the sequencing revealed was that a “mysterious population” of early H. sapiens once roamed across northern Asia who were hunter-gatherers. The femur bone was discovered by Russian artist Nikolai Peristov in 2008 along Siberia’s Irtysh River. He dug the bone out of the riverbank and showed it to a police forensic scientist who identified it as likely human.
The bone is a left femur and eventually found its way to the Max Planck Institute for Evolutionary Anthropology in Germany. There it was dated using C14 dating techniques. The bone was highly fossilized. Turns out the femur bone was older than any previous modern human fossil ever dated. It was also discovered the bone had well preserved DNA so the genome was sequenced as well. In the end the bone was dated at between 43,000—47,000 years old which is nearly twice the age of what is now the second oldest H. sapien bone ever found and sequenced. However, it is important to note that older archaic human genomes that are not H. sapiens have been sequenced in the past.
There was no archaeological site connected to the find and that suggested that this male hunter-gatherer and possibly his group roamed far and wide in northern Asia searching for food. Paleoanthropologists suspicion that Ust’-Ishim Man most likely descended from an extinct group that is closely related to early H. sapiens who migrated out of Africa more than 50,000 years ago.
Researchers also found something else interesting about the DNA. About 2% of Ust’-Ishim Man’s DNA came from Neandertals! That means there was interbreeding going on between H. sapiens and Neandertals about 45,000 years ago! Ironically, modern humans today who are non-Africans have about the same amount of Neandertal DNA in them too, still. It’s believed that the common ancestors of Asians and Europeans interbred with Neanderthals once they migrated out of Africa and encountered Neanderthals in the Levant (Middle East).
Long Neanderthal DNA segments found in Ust’-Ishim Man’s DNA suggest interbreeding between early H. sapiens and Neanderthals was taking place between roughly 37,000 and 86,000 years ago. Chromosomes from both the father and mother get mixed together in each generation and over time DNA segments become shorter.
As current theory stands paleoanthropologists believe early H. sapiens began to migrate out of Africa around 100,000 years ago or before. They are believed to have reached Asia more than 75,000 years ago.
H. sapien like bones have been found in the Levant (Middle East) that are older than 100,000 years old and stone tools have been found in India that have been dated to about 70,000 years old. These stone tools found in India have led scientists to believe our ancient human ancestors migrated out of Africa and too, a southern route that eventually led them to settle in Australia and Oceania but, Ust’-Ishim Man appears to have been a member of a group that may have taken a northern route into Asia.
Not all researchers are in agreement when it comes to Ust’-Ishim Man, however, as is typically the case. Some believe Ust’Ishim Man was part of a “population boom” that was going on around 45,000 years ago and that means H. sapiens were definitely in Asia by that time. They suspect that future discoveries and the sequencing of other ancient DNA will paint a very complicated picture when it comes to the peopling of Asia.
Of course there were likely earlier human populations in Asia by the time H. sapiens migrated out of Africa and this “population boom” may well over overshadowed those other hominid populations. The Replacement Theory (Out of Africa Theory) holds that humans migrated out of Africa and evolved. The Multi-Regional Theory holds that early hominids left Africa and evolved independently of those migrating out of Africa around 100,000 years ago. I think the Multi-Regional Theory holds the key to where the Neandertals came from as apparently they were already in Europe, the Levant, and Asia by the time the people of Ust’-Ishim Man began to migrate into norther Asia. Neandertal fossil remains have been found in Siberia at Denisova Cave along with fossil remains of another species of human known as the Denisovans and they, as well, interbred with the Neandertals.
So the question is just exactly where did the Neanderthals come from and when? Where they descendents of some group that came out of Africa long before we know OR were they some species of hominid that evolved independently of those in Africa? The question is still a matter of debate. One thing is certain and that is that human prehistory is more complicated than we thought and it is apparently not so clear cut. Human evolution is not a tree. It’s far more like an ever-increasing twisted bush!