A genetic variant inherited from our ancient Neanderthal relatives and thought to confer heightened fertility has been found in modern humans. The new research suggests almost one in three European women carry some degree of the gene variant.
The research homed in on a particular gene variant that codes for progesterone receptors. These receptors help the hormone progesterone bind to cells maintaining, among other things, healthy pregnancies.
Looking back in time, the new research from scientists at the Max Planck Institute for Evolutionary Anthropology in Germany and the Karolinska Institutet in Sweden suggests the oldest trace of the genetic variant in modern humans can be tracked to a 40,000 year-old individual found in China. Upon examining ancient Neanderthal genomes the variant was traced to over 100,000 years ago.
Hugo Zeberg, lead author on the study, notes several instances of interbreeding between Neanderthals and modern humans have been identified from ancient DNA studies. However, it is suspected this genetic variant may have originated through interbreeding sometime between 47,000 and 65,000 years ago.
"The progesterone receptor is an example of how favorable genetic variants that were introduced into modern humans by mixing with Neanderthals can have effects in people living today," says Hugo Zeberg.
Examining UK Biobank data the researchers found out of 244,000 modern women, 29 percent carried one copy of the gene variant, and three percent carried two copies. The women with this ancient Neanderthal gene variant were found to experience fewer miscarriages and suffer from fewer bleeding events in early pregnancy, compared to women without the particular gene variant. The women with the gene were also found to have more siblings than women without the gene, which the researchers suggest is a viable proxy to indicate increased fertility.
"The proportion of women who inherited this gene is about ten times greater than for most Neanderthal gene variants," says Zeberg. "These findings suggest that the Neanderthal variant of the receptor has a favorable effect on fertility."
The new study was published in the journal Molecular Biology and Evolution.
Source: Max Planck Institute