An article published in the journal “Nature Ecology and Evolution” reports the identification of new fossil bones belonging to the Denisovans, the hominin species still mysterious from various points of view. A team of researchers led by Katerina Douka conducted a very sophisticated analysis of nearly 3,800 bone fragments too small to be identified by normal methods and found five that belonged to humans, four containing enough DNA fragments to establish that three belonged to Denisovans and one to a Neanderthal. The bones were found in a layer of Denisova Cave dating to as early as 200,000 years ago, making them some of the oldest human fossils from which it was possible to extract DNA. They’re important fossils also because they were discovered in the same sediments as animal remains and stone tools that offer information about that people’s life.
After the identification of a new human species in 2010 thanks to genetic techniques, excavations in Denisova Cave in Siberia continued. It’s a very complex task because the cave has been inhabited by different populations of Denisovans, Neanderthal, and Homo sapiens over many millennia, and many remains are just fragments. It’s the only known site so far where evidence of the presence of these three human species has been found.
For four years, a team led by Dr. Katerina Douka worked to extract proteins from nearly 3,800 bone fragments found in the oldest layers of Denisova Cave, dating back to as early as 200,000 years ago. Samantha Brown, who at the time was a doctoral student part of the ERC (European Research Council) FINDER Project with the aim of finding new Denisovan remains, identified five human fragments thanks to the presence of traces of proteins.
Postdoc researcher Diyendo Massilan led the genetic analysis of human fossils. He and his colleagues were able to extract mitochondrial DNA from four of those fragments, allowing them to identify three as Denisovans and one as a Neanderthal. They’re among the oldest human fossils from which DNA was extracted, an amazing result even for the researchers.
The discovery of animal remains together with those of Denisovans offers information on the diet of that population. They hunted herbivores such as bison, roe and red deer, gazelles and saiga antelopes, and even woolly rhinos. They are more or less the same species they kept on hunting for many millennia. Between 130,000 and 150,000 years ago, Neanderthals appear in the cave and the bone found in this study belongs to one of them.
The stone tools discovered together with the fossils are also important because they offer information on those ancient Denisovans’ culture. The level of sophistication indicates that the first Denisovans to inhabit the cave must already have had considerable experience in working stone, which they collected in the nearby Anui River. The possibility of attributing stone tools to a certain population also offers the possibility of carrying out archaeological studies to reconstruct the history of this ancient human species e get to know their culture.
Advances in paleogenetics, which studies the DNA of extinct species, offer results that were unthinkable not many years ago. Denisova Cave is important for the amount of remains left by three human species but only now researchers can identify some of the many bone fragments found inside it. Studies in recent years show the complex history of humanity with interbreedings between various species and migrations. Just a few bones have been attributed to the Denisovans, a still-mysterious species in various ways whose genes are still present in various modern human populations. Studying the Denisovans is important in reconstructing the history of humanity.
