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Early hominin works with tools. (procy_ab/AdobeStock)

Finger Bone Points the Way to Revealing Denisovan DNA Secrets

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A Denisovan finger fossil is revealing secrets about this extinct Stone Age race.

A decade ago, scientists excavating Denisova Cave , an ancient archaeological site in southern Siberia, discovered fossils of a previously unknown group of ancient humans. Nature reported in February this year how DNA had been found preserved in a finger bone and that this remote shelter was “one of the most important archaeological sites in the world.”

Denisova Cave: Soloneshensky District, Altai Territory (Demin Alexey Barnaul/CC BY SA 4.0)

Denisova Cave: Soloneshensky District, Altai Territory (Demin Alexey Barnaul/ CC BY SA 4.0 )

A 2012 Science News article said that the pinkie-bone contained “the first known Denisovan DNA” and now a team of researchers led by paleogeneticist E. Andrew Bennett of Paris Diderot University has identified “the rest” of the approximately 13-year-old female Denisovan’s  finger bone . And according to the new paper published on September 4 in  Science Advances , “Unexpectedly”, this ancient finger looks more human than Neanderthal, the scientists reported.

Anthropologists now know that Denisovans inhabited regions of Asia between 300,000 to 50,000 years ago and in a report in Harretz, Prof. Eva-Maria Geigl of Institute Jacques Monod, University of Paris explains: “Denisovan fingers were gracile like those of modern humans, explains, and not stubby digits with blunt ends like those of their sister species the Neanderthals.”

Replica of a Denisovan finger bone fragment, originally found in Denisova Cave in 2008. (Thilo Parg/CC BY SA 3.0)

Replica of a Denisovan finger bone fragment, originally found in Denisova Cave in 2008. (Thilo Parg/ CC BY SA 3.0)

Travelers of Ancient Planes

The newly identified finger fossil was recovered from Denisova Cave by Russian scientists in 2008 and belongs to the species of archaic human that is neither Neanderthal nor Homo sapiens . It was the only fragment of the species known to science until it was reported in May that a Denisovan jaw bone had been discovered 2,400 kilometers (about 1,500 miles) from the Siberian cave, on the Tibetan Plateau.

The new paper informs that the scientists “cut the specimen into two” and sent pieces to separate DNA-research teams for independent testing. One part was sent to the Max Planck Institute in Germany and the other to Geigl’s lab at the University of Berkeley where her team joined forces with researchers at the University of Bordeaux and the University of Toronto.

Mitochondrial DNA is typically inherited from the mother and Bennett’s group found the mitochondrial DNA extracted from one finger matched that from the other, confirming the bones came from the same female. In comparisons with Neanderthal and  Homo sapiens  specimens, the dimensions and shape of the entire Denisovan pinkie bone fell within the range of measures for “ancient and modern humans, not Neandertals,” the researchers say.

Reaching Deep into Pre-History

Genetic DNA studies suggest that proto-Neanderthals and precursor- Homo sapiens split about 700,000 years ago and that Europe’s ancestral Neanderthal line split around 400,000 years ago, into Neanderthals in the West and Denisovans in the East. It is believed Neanderthals and Denisovans coexisted in Denisova Cave, which is evident in that archaeologists identified a 90,000 year-old-bone belonging to a first-generation Neanderthal-Denisovan hybrid teenage girl.

This bone fragment ('Denisova 11') was found in 2012 at Denisova Cave in Russia and represents the daughter of a Neanderthal mother and a Denisovan father. (T. Higham/ University of Oxford)

This bone fragment ('Denisova 11') was found in 2012 at Denisova Cave in Russia and represents the daughter of a Neanderthal mother and a Denisovan father. (T. Higham/ University of Oxford )

The artifacts and remains found in Denisova Cave are thought to be among the oldest in Europe, but they were rivaled earlier this year with the discovery of teeth dating to 200,000 BC in Yanhui Cave in Tongzi, southern China. A report in Science Direct  said the Tongzi teeth “do not fit the morphological pattern of classic  H. erectus” meaning they were not from Homo erectus or Neanderthals.  This, said the scientists, expands our understanding of the “morphological diversity of the Asian Middle Pleistocene hominins” and that more than one paleodeme existed in East Asia during this period.

Where Did They Come From, Where Did They Go?

Scientists debate about the destiny of Denisovans and as new data is gathered some researchers are journeying into new territory. In April this year, an Ancient Origins report reviewed a new book  Denisovan Origins: Göbekli Tepe, Hybrid Humans and the Genesis of the Giants of Ancient America,  showing how the Siberian Denisovans had “a huge impact on the spread of Upper Paleolithic traditions.” While most scientists would agree that this impact affected south and east of Siberia to the as far west as the Atlantic coast of Europe, the authors of this book suggest that perhaps they found a way into the Americas.

While researchers and scientists argue as to what happened to the Denisovans, and where they went, the question of where they came from is still seemingly tantalizingly just out of our reach.

Top image: Early hominin works with tools. (procy_ab/ AdobeStock)

By Ashley Cowie

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