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Denisovans: Who were these ancestors of the Neanderthals and Homo sapiens?
By Catholic Online (NEWS CONSORTIUM)
August 31st, 2012
Catholic Online (www.catholic.org)
August 31st, 2012
Catholic Online (www.catholic.org)
Denisovans, an entire race of primitive man has been reconstructed from a single finger bone and two teeth. These examples of prehistoric humans share the same genetic makeup as the Neanderthals and modern man, and yet scientists are at a loss to who they exactly were.
LOS ANGELES, CA (Catholic Online) - The slim case for their existence, the finger and two teeth, were found in a cave in southern Siberia, and give some preliminary clues.Sequencing the Denisovan genome, scientists have arrived at a quality that is about as high as the genome of a person alive today. Modern scientists today can learn about as much genetically about a person who lived tens of thousands of years ago as they can about a living person. Recent findings have delivered a wealth of insight about ancient people who once roamed the Earth.
Lead researcher Svante Paabo, a biologist at the Max Planck Institute of Evolutionary Anthropology, says that by comparing the genetics of modern humans with relatives in the evolutionary tree, it appears there are more than 100,000 genetic mutations that most people alive today share. There are still many that our closest relatives in the evolutionary line did not have, he says.
"This is essentially a 'genetic recipe' " for being a modern human, Paabo said in an e-mail. "Scientists can now start working on understanding how we differed from Denisovans and Neanderthals."
Although some of the Denisovans' remains were found in southern Siberia, their genetic signature is not present anywhere apart from islands in the Pacific. About three percent to five percent of the DNA of people from Melanesia (islands in the southwest Pacific Ocean), Australia and New Guinea as well as aboriginal people from the Philippines are from the Denisovans.
These isolated areas are the only places where Denisovan DNA has been found, Paabo says. By process of elimination, the Denisovans must have been in Southeast Asia at one time.
Everyone who lives outside Africa today probably has some Neanderthal DNA in them, Paabo says.
Scientists aren't sure how old the finger bone used for the DNA sequence really is. Archaeologists date it to 30,000 to 50,000 years old. Biologists who conducted this study believe it could be 80,000 years old, belonging to a juvenile female. She may have had dark skin, brown hair and brown eyes, based on genetic associations.
It also appears that the Denisovans mixed with (and mated with) indigenous people in Papua New Guinea and Australia, Paabo said.
"They probably became extinct about the same time as Neanderthals when modern humans spread around the world," Paabo said.
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