The Denisovans, also known as Denisova hominins, were an ancient species or subspecies of archaic humans that roamed Asia during the Lower and Middle Paleolithic.
In 2010, amongst the thousands of bones found by archaeologists at the Denisova cave in Siberia’s Altai Mountains was a portion of the little finger of a young girl. This small bone was transported, along with all the others, to the Max Planck Institute’s ancient DNA lab in Leipzig, Germany. When the bone was analyzed it proved to be very different from all the others, for it revealed a complete genome of what was believed to be a whole new type of human being.
This new species of human has become known as the Denisovans, after the cave where the little girl’s finger was found. The members of this family are believed to have mated with Neanderthals and modern humans over the past 100,000 years.
The only evidence of the existence of the Denisovans is that portion of a little girl’s finger, along with three molar teeth that were found at the same cave. Everything that has been found out about these ancient people is the result of DNA analysis of these four original sources. This, in itself, is groundbreaking. Never before has the history of an ancient people been revealed by nothing more than its genome sequence as opposed to the fossil and artifact record.
The researchers at the Max Planck Institute were able to successfully extract DNA from all four of the specimens. From this, they determined that the finger and three teeth all came from different people. Furthermore, they found that two of the four lived around 65,000 years before the other two. From that, it is clear that the Denisovans were around for a considerable period of time.
The ancestors of the Denisovans lived in Africa between 550,000 and 765,000 years ago. These people spread into both Europe and Asia. Those who settled in Europe became the Neanderthals with the Asians becoming the Denisovans. For an unknown length of time, they evolved separately but then their paths crossed and interbreeding took place.
Archaeological findings reveal that Neanderthals were using quite advanced tools around 100,000 years ago. Based on the similar DNA make-up of the Denisovans, archaeologists believe that they, too, were using such tools for hunting and gathering at that time. A large number of artifacts have been found at the Denisova cave but it is impossible to know whether they were used by the Denisovans or the Neanderthals. Among the artifacts found at the site were thick, triangular stone points that were typical of Neanderthal artifacts along with less common slender stone blades that have been associated with modern humans of the Upper Paleolithic tradition. These may have been made by the Denisovans but there is nothing concrete to tie them to these artifacts.
Due to their fragility, it was not possible to do radiocarbon dating on the teeth and finger bone found at the Denisova cave in 2010. As a result, it is very difficult to say when the little girl and her fellow Denisovans lived in and around the area. The hope is that larger bones will be found but this seems unlikely. All of the other bones found at the Denisova cave had been chomped to bits by hyenas which makes it almost impossible to get any meaningful data from them, or even to tell whether they are the bones of a human or an animal.
Researchers, however, have not been limited to just four human fragments found at the Denisova cave in their attempts to learn more about these ancient people. They have also looked to the current human gene pool. People living on tiny islands in Southeast Asia and Oceania have genes with up to 6 percent of Denisovan DNA. It is interesting to note though, that no populations have been identified with Denisovan-like DNA in the region around the Denisova cave. From that, it has been extrapolated that the Denisovans moved extensively around Asia, including Siberia and Australasia.
From the DNA record, researchers believe that the Denisovans were genetically equipped to survive in cold climates. A version of the EPAS1 gene, which is a regulator of blood hemoglobin, has been identified in Tibetan people, allowing them to survive in environments above 13,000 feet where the oxygen level in the air is extremely low. It is thought that the Tibetans inherited this gene from the Denisovans. This gene in the Tibetans is different from all other humans but nearly identical to that found in the Denisovan bone and teeth.
Credits:
Illustration - Jonathan Benbow bongwedesign.com
Script - Steve Theunissen
Voice Actor - James Fowler
