UCT researcher helps determine earliest human genome

23 October 2014 - 18:20 By Dominic Skelton
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A research team has determined the genetic make-up of the earliest modern human- a 45 000-year-old human male that was discovered in western Siberia, near the town of Ust’-Ishim.

The paper, published today in the science journal Nature has contributions from a researcher based at the University of Cape Town’s Archaeology department, Domingo Carlos Salazar García.

The research found that a group of the Ust’-Ishim man’s ancestors colonised Asia before 45 000 years ago.

He is thought to have lived at the time of the expansion of modern humans into Europe.

When genomes taken from the man’s femur were compared to 50 different modern populations, it was discovered that the individual was more closely related to people outside of Africa than those within it; meaning that he was an early representative of the population that left Africa.

The Ust’-Ishim man’s genomes were compared to that of modern-day people in Europe and East Asia, the lengthened segments in his Neanderthal DNA (All present- day people outside Africa have some) indicated that interbreeding (admixture) with Neanderthals took place between 50 000 and 60 000 years ago. 

“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”, said Svante Pääbo, one of the study’s authors. 

“It is very satisfying that we now have a good genome not only from Neanderthals and Denisovans, but also from a very early modern human.”  

Analysis of the Ust’-Ishim man suggested that he consumed freshwater resources on a regular basis, something not directly observed on Neanderthals until now.

"These results are important, since the consumption of aquatic resources portraits a wide-spectrum dietary pattern for these Eurasian pioneer early modern human populations not observed yet for Neanderthals of the region", says García.

"Probably the ability to have this dietary plasticity helped them to adapt to extreme northern environments, helping them in their Eurasian 'enterprise' compared to Neanderthals, which eventually disappeared"

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