According to a new study, a genome analysis method has confirmed that Neanderthals interbred with the ancestors of Eurasians.
Currently there are two hypotheses reasoning the genetic similarities between Neanderthals and humans. The first is that certain human populations, later known as modern Eurasians, evolved in isolated patches in Africa that allowed them to stay genetically similar to Neanderthals after they split from their shared common ancestor. The second hypothesis is that Neanderthals that left Africa interbred with the ancestors of Eurasians.
To test which of these hypotheses is true; University of Edinburgh researchers conducted a new genome analysis and found the latter scenario to be true.
"Our approach can distinguish between two subtly different scenarios that could explain the genetic similarities shared by Neanderthals and modern humans from Europe and Asia," said study co-author Konrad Lohse, a population geneticist at the University of Edinburgh, in a news release.
This analysis was different because it was conducted on genomes of Neanderthals, Eurasians, Africans and chimpanzees rather than comparing genomes from many modern humans.
"We did a bunch of math to compute the likelihood of two different scenarios," said Laurent Frantz, study co-author from Wageningen University, according to The Verge. "We were able to do that by dividing the genome in small blocks of equal lengths from which we inferred genealogy."
"Our analysis shows that a model that involves interbreeding is much more likely than a model where there was sustained substructure in Africa," he added.
The new genome analysis method used in the current study was developed while studying the history of insect populations in Europe and island species of pigs in South East Asia, some of which are extremely rare.
The findings of the current study debunks a 2012 study which stated interbreeding between Neanderthals and humans was an impossible hypothesis.
Neanderthals and modern humans share many genetic similarities. In November last year, Oxford University and Plymouth University researchers found the presence of ancient Neanderthal viruses in modern human DNA.
More recently, biologists claimed that modern Europeans share a number of genes involved in the build-up of certain types of fat with Neanderthals. The same genes were not seen in people from Asia and Africa.
The new study was published in the April 2014 issue of the journal GENETICS.
