Scientists say they have discovered the remains of an ancient female whose mother was a Neanderthal and whose father was Denisovan.
Neanderthals and Denisovans are early human species that have been extinct for thousands of years. The discovery marks the first time scientists have found the remains of a child created by these two kinds of early humans.
The researchers found the 90,000-year-old pieces of bone in southern Siberia. The team published their findings in the journal Nature on Wednesday.
In this 2011 photo provided by Bence Viola of the University of Toronto, researchers excavate a cave for Denisovan fossils in the Altai Krai area of Russia. (Bence Viola/Department of Anthropology - University of Toronto/Max Planck Institute for Evolutionary Anthropology via AP)Why the discovery is important
Neanderthals lived in Europe and Asia. Remains of Denisovans are known only from the cave where the bone was found. Both groups disappeared by about 40,000 years ago.
Past genetic studies have shown evidence of sexual relations between the two groups, as well as with our own species, Homo sapiens. The unions show in the genetic structure, or DNA, of today's people. But the new study is the first to identify a first-generation child with Neanderthal and Denisovan parents.
Svante Paabo is one of the lead researchers of the study. He is a geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. Paabo said he was surprised the bones were found. Both Neanderthal and Denisovan remains are rarely discovered anywhere in the world. So finding an actual child of the two groups seemed like unusually good luck, Paabo said.
The discovery is also interesting because the two groups were more different from each other than any two present-day human groups.
"The fact that we stumbled across this makes you wonder if the mixing wasn't quite frequent," said Paabo,
Other opinions
Ron Pinhasi is a physical anthropologist at the University of Vienna who was not involved in the study. He noted that the discovery does not answer how often Neanderthals and Denisovans mated. If they mated often, he said, the DNA of Neanderthals and Denisovans would not show such major differences.
Anders Eriksson is an evolutionary population geneticist at King's College London who was not involved in the study either. He suggested that the DNA could be looked at in several different ways.
"I think they convincingly showed that genetically this individual falls halfway between the Neanderthal and Denisovan fossils found in the same cave," said Eriksson. "But I'm less convinced that it is necessarily a first-generation offspring of a ... Neanderthal and Denisovan."
The fossil could instead have come from a population with nearly an equal mix of Neanderthal and Denisovan relatives, he observed. And it will take studies of more fossils to find this out.
What else can we learn?
The authors of this week's report said the small pieces of bone likely came from the arm or leg of a female who was at least 13 years old at the time of death. They call her "Denisova 11."
The researchers compared her DNA with other ancient DNA. They learned that the genes from her mother were more closely related to Neanderthals who lived later in Europe than other Neanderthal remains from the cave.
This finding suggests that Neanderthals moved westward over time.
Svante Paabo said the latest discovery suggests that the now-extinct ancient relatives of humans were not killed off by warfare, as many experts believe. Instead, it supports a theory that our ancient relatives combined with modern humans through sexual relationships.
Frank Jones reported this story for the Associated Press. Pete Musto adapted it for VOA Learning English. Kelly Jean Kelly was the editor. We want to hear from you. What do you think scientist will learn from similar discoveries in the future? Write to us in the Comments Section or on 51VOA.COM.
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