How a Girl’s Pinky Led to the Discovery of a New Human Species

In south-Western Siberia there is a small gave that does not seem like much. It is in the Altai mountains and was largely disregarded by archaeologists. The cave is named the Denisova Cave after a Russian hermit that was known to inhabit the cave in the 18^th century. In the 1970s the cave was explored by a paleontologist named Nikolai Ovodov who wanted to find the remains of canids.

In 2008 the cave took on new interest when Michael Shunkov from the Russian Academy of Sciences and other archaeologists from the Institute of Archaeology and Ethnology of Novosibirsk explored the cave. Inside they found numerous human artifacts including a bracelet that was found to be over 40,000 years old. There were also human artifacts and remains that went back over 125,000 years.

Much of what was gathered from the cave was assumed to be Neanderthal, the species that was an archaic human species that died out 40,000 years ago. When the bones were later examined they found what appeared to be the pinky bone of a young child, what many believe to be a young girl of around 6 or 7 years old. She was named woman X despite being just a child. A team in Germany destroyed the bone in order to test the mtDNA or the mitochondrial DNA that is passed down from the mother.

The team read the sequences of mtDNA 156 times to ensure what they were seeing was accurate. Then they compared those results with that of 54 modern humans, a 30,000-year-old modern human found in Russia and six Neanderthals. What they discovered shocked them, and suggested that much of what was believed about ancient humans might not be true.

Click Next on to see what they discovered in the DNA.

How a Girl’s Pinky Led to the Discovery of a New Human Species — A replica of the pinky finger bone. www.dailymail.co.uk

It is pretty well known that at some point modern humans started to bred with Neanderthals and therefore modern humans do share some DNA with the ancient species. Neanderthal DNA different from modern human DNA at 202 nucleotide positions. The DNA of the little girl’s pinky bone differs from modern humans at 385 nucleotide positions. This suggested that the little girl’s ancestors migrated out of Africa long before the Neanderthals did, more than 500,000 years before.

However, when nuclear DNA was examined and the girl’s genome sequenced it was clear that she belonged to a species that diverged from the Neanderthals 640,000 years ago and from modern Africans 804,000 years ago. The DNA is different from any Neanderthal DNA found in Eurasia and from that of any modern human. The new species, named Denisovan existed at the same time as Neanderthals and modern humans and evidence has been found to suggest that this species bred with both the Neanderthals and modern humans.

Further evidence was gathered in the Denisova cave that proved the existence of a distinct archaic human species. A molar was found that looked nothing like the teeth of a Neanderthal or a modern human. The molar actually held characteristics that were similar to that of homo erectus. Testing revealed the molar belonged to a separate individual from the little girl but still a member of the same population.

What is puzzling today is that Denisovan DNA is only found in Melanesians and aboriginal Australians. This suggests that at some point the Denisovans migrated from Siberia down to Melanesia and remained there. Evidence has suggested that Denisovans once lived throughout east Asian but eventually ended up in Melanesia and South-East Asia as a point of last refuge.

Very little is known about the lifestyle or the appearance of the Denisovans. The best evidence to date on Denisovans were the small bones and teeth found in the cave. However, some believe that previously identified Neanderthals may now be found to have more in common with the Denisovan DNA rather than with the Neanderthal DNA. Scientists have theorized that the Denisovans might have been of an even stockier build than the Neanderthals based on the appearance of the molar and the size of the child’s finger.

What has been learned about the Denisovans is what they provided modern humans through interbreeding. Denisovans provided genes that can recognize viruses, raise blood glucose levels and break down fats. Some believe that this is what allowed humans to quickly adapt to the climate, diseases and food that they encountered as they migrated around the world.