Researchers have sequenced the genome of a 45,000-year-old modern human male from western Siberia for the first time, reavealing secrets of ancient mating and migration patterns.
The ancient individual is the oldest modern human to ever undergo genome sequencing, and comparing his genome to those of people who lived later on in Europe and Asia could provide insight into their migration, the Max Planck Institute for Evolutionary Anthropology reported. All that is left of the subject is a relatively complete femur, but this small bone was enough to reveal some ancient secrets.
"The morphology of the bone suggests that it is an early modern human; that is an individual related to populations that are the direct ancestors of people alive today" said Bence Viola, an anthropologist who analyzed it. "This individual is one of the oldest modern humans found outside the Middle East and Africa."
The recent findings suggest the mash up between modern humans and Neanderthal took place between 50,000 and 60,000 years ago. The piece of the skeleton, dubbed the Ust'-Ishim bone after the Siberian village it was discovered in, is believed to be equally related to people in East Asia and people that lived in Europe during the Stone Age.
"The population to which the Ust'-Ishim individual belonged may have split from the ancestors of present-day West Eurasian and East Eurasian populations before, or at about the same time, when these two first split from each other," team leader Svante Pääbo said. "It is very satisfying that we now have a good genome not only from Neandertals and Denisovans, but also from a very early modern human"
The findings suggest the Ust'-Ishim individual may have belonged to a population of immigrants into Europe and Central Asia that have since died out. The man only possessed about 2 percent Neanderthal DNA, which is similar to what is seen in today's East Asians and Europeans; the length of the ancient individual's Neanderthal DNA segments is much longer than in present-day humans because they had not yet been reduced in size through the generations.
"This allowed us to estimate that the ancestors of the Ust'-Ishim individual mixed with Neandertals approximately 7,000 [to] 13,000 years before this individual lived or about 50,000 to 60,000 years ago, which is close to the time of the major expansion of modern humans out of Africa and the Middle East", said Janet Kelso, who led the computer-based analyses of the genome.
The research also allowed the scientists to estimate the rate at which mutations accumulate in the human genome. The findings suggest between one and two mutations per year tend to accumulate in the genomes of populations in Europe and Asia since the Ust'-Ishim man walked the Earth.
The findings were published in a recent edition of the journal Nature.
