A piece of bone from a cave in Russia has yielded what may be the biggest archaeological find of the year, media reported on August 30.
The bone belonged to an ancient human who had a Neanderthal mother and a Denisovan father. Nicknamed "Denny," the specimen is the first scientists have found that is a first-generation offspring from such interbreeding.
Scientists said the find may provide evidence that hominins interbred more often than previously thought. It also suggests that extinct groups like Neanderthals may not have died out, but rather were absorbed by the human species.
In prehistory, members of our species interbred with at least two other ancient humans: the Neanderthals and the mysterious Denisovans, who are known only from fragments of bone and teeth discovered in the Denisova Cave in Russia.
These interbreeding events were thought to be rare. But a few years ago, archaeologists found a 90,000-year-old bone fragment in the Denisova Cave.
A photo of the bone fragment found at the Denisova Cave
Samantha Brown, then at the University of Oxford, discovered that it came from a hominin by examining the proteins preserved inside it. Based on the structure of the bone, her team postulated that Denny died at about age 13.
After examining Denny’s DNA, scientists discovered that the individual in question was female, and that she had astonishing parentage. Her DNA was almost half Neanderthal and half Denisovan.
Denny’s mitochondrial DNA, which is inherited only from mothers, is Neanderthal. Therefore, her mother was Neanderthal and her father Denisovan.
The significance of the find is that it shows "interbreeding among different human lineages was more common than previously thought," Katerina Harvati-Papatheodorou of the University of Tübingen, Germany, told New Scientist magazine.
A 40,000 year-old Homo sapiens with a Neanderthal ancestor recently found in Romania also bolsters this notion.