Natural selection purged Neanderthal genes in modern humans: study

Modern human genomes contain only a small amount of Neanderthal genes or DNA because natural selection purged many of our caveman relative's genes during the process of evolution, according to a new study.

Researchers believe that Neanderthals and modern humans interbred nearly 50,000 years ago, when modern humans were spreading out of Africa. Initially, Neanderthal DNA accounted for the interbred species, but now Neanderthal DNA makes up just around 1.5 to 2.1 per cent of the genomes of humans outside Africa.

Ivan Juric, an evolutionary biologist at the UC Davis who led the study, concluded that the evolutionary mechanism of natural selection purged many of our caveman relative's genetic material because of their potential negative effects.

Sharing findings of the study, Juric added, "In this way, the evolutionary mechanism of natural selection ensured that over time, Neanderthal segments containing deleterious alleles get removed from populations faster than Neanderthal segments not containing deleterious variants."

The researchers also indicated that future researches could be focused at investigating which genetic variants come from extinct relatives of modern humans.

The findings of the new research were detailed in a recent edition of the open access peer-reviewed journal PLOS Genetics.