Neanderthals interbred with other hominids 100,000 years ago

Washington, Aug 23 : A recent study by a researcher from the University
of Southern California has revealed that individuals of European descent
could be up to five percent Neanderthal, while West Africans could be
related to an archaic human population.
Professor Vincent Plagnol in the University's Department of Molecular
and Computational Biology has said that a study of genes of people from
Yoruba and individuals living in Utah with ancestry from Northern and
Western Europe revealed the existence of archaic DNA in the genes.

This countered the view that modern humans left Africa and replaced all
other existing hominid populations, he said.
"Instead of a population that left Africa 100,000 years ago and replaced
all other archaic human groups, we propose that this population
interacted with another population that had been in Europe for much
longer, maybe 400,000 years," Discovery News quoted Prof. Plagnol,
co-author of the study as saying.
For their study, Prof. Plagnol and his colleague Prof. Jeffrey Wall
analyzed patterns of ancestral linkage in 135 modern individuals.

Using statistics and computer modelling, they focused on linkage
disequilibriums, or sections within genes that did not make sense if
only modern human matings were considered.
According to the paper, which was published in PLoS Genetics, missing
genetic links only fit if some other hominid population was introduced
into the model.

"We considered the data from modern human DNA and fitted a model to
explain what we see. We found that a simple model cannot explain the
data if we do not add an 'ancestral population.' If this population did
not cross with modern humans — or almost did not — the effect is too
small to explain the data. We find that a rate of five percent is what
is needed to explain what we see," said Prof. Plagnol.
They said that portions of the European genome, such as those associated
with nuclear DNA might still harbour the Neanderthal imprint.

Prof. Plagnol said different parts of the genome hade different
ancestry, so an individual could have a fraction of a certain chromosome
that was inherited from a Neanderthal, but then possess "very typical
homo sapiens mtDNA".
Alan Templeton, professor of Evolutionary and Population Programs at the
University of Michigan, who also conducted DNA studies and came to
similar conclusion said, that "humans who were in Africa and humans who
were in Eurasia were regularly interchanging genes".

"There was interbreeding and when humans came out of Africa 100,000
years ago they did not replace these other human populations in
Eurasia," he said.

--- ANI