Researchers discover why modern humans lost much of Neanderthal DNA

Researchers discover why modern humans lost much of Neanderthal DNA

Neanderthals and modern humans diverged from a common ancestor nearly half a million years ago and the two species interbred thousands of years ago, but genomes of modern humans have a very small amount of Neanderthal genetic material or DNA. Now, a new study claims to have solved that mystery.

Humans and Neanderthals interbred nearly 50,000 years ago, when modern humans started spreading out of Africa. But, Neanderthal DNA makes up just 1 to 4 per cent of the genomes of today's non-African individuals.

A team of researchers led by Ivan Juric of UC Davis conducted a study to understand how modern humans lost their Neanderthal DNA. The study suggested that natural selection removed several Neanderthal alleles from the genome due to potential negative effects.

The researchers estimated that gene variations managed to persist in Neanderthals because of Neanderthals' smaller population size than that of humans. These alleles became subject to natural selection when they were transferred into the human genome, and got removed over time.

Sharing findings of their study, Juric said, "After Neanderthals started mating with humans, natural selection in the larger human population started purging those mutations."

The researchers reported their findings in the Nov. 8th edition of the PLOS Genetics -- an open access peer-reviewed journal published monthly by PLOS.