Some human individuals are more fertile than others, and figuring out why is challenging for biomedicine. However, a study has just been published that offers a clue as to why some women would be especially fertile – it’s all due to a gene inherited from a Neanderal ancestor.
Homo sapiens and Homo neanderthalensis lived together and had offspring. This hybridization, although punctual, gave rise to a branch of descendants that conserved genes of the Neanderthals. These genes would still survive today, in European women who are more fertile than the average. This is the conclusion of a study published in Molecular Biology and Evolution by researchers from the Max Planck Institute for Evolutionary Anthropology in Germany and the Karolinska Institute in Sweden.
According to the researchers’ results, one in three women in Europe inherited the Neanderthal receptor for progesterone , a genetic variant associated with increased fertility, less bleeding during early pregnancy and fewer miscarriages.
Progesterone is a hormone that plays an important role in the menstrual cycle and in pregnancy. According to Hugo Zeberg, a researcher at the Department of Neuroscience at the Karolinska Institute and the Max Planck Institute for Evolutionary Anthropology: “The progesterone receptor is an example of how favorable genetic variants that were introduced into modern humans by mixing with Neanderthals can have effects on the people who live today. “
Analyzes of biobank data from more than 450,000 participants, including 244,000 women, show that almost one in three women in Europe has inherited the H. neandertalensis progesterone receptor. 29% of European women carry one copy of the Neanderthal progesterone receptor and 3% of them have up to two copies.
Most fertile women
As Hugo Zeberg explains: “The proportion of women who inherited this gene is approximately ten times higher than for most variants of the Neanderthal gene. These findings suggest that the Neanderthal variant of the receptor has a favorable effect on fertility.”
The study shows that women who carry the Neanderthal variant of the progesterone receptor tend to have less bleeding during early pregnancy, fewer miscarriages, and give birth to more children. Molecular analyzes revealed that these women produce more progesterone receptors on their cells, which can lead to increased sensitivity to progesterone and protection against miscarriage and early bleeding.
Our Neanderthal part
While Neanderthals appeared to possess this fertile advantage, they did not thrive. The causes of its extinction are still under debate , but inbreeding, nutritional deficit or competition with sapiens are being considered.
This is a fascinating finding that reminds us that we are still linked to a branch of hominids that we became related to at some point in the past. Both species, sapiens and Neanderthals, lived together for at least 10,000 years on the European continent.
Neanderthals have been commonly described as almost bestial beings, far removed from our species. However, paleontological research shows that they had very complex social characteristics and made great technical advances, in terms of tools and tools.
References:
“The Neanderthal Progesterone Receptor”. Hugo Zeberg, Janet Kelso and Svante Pääbo. Molecular Biology and Evolution, online 21 May 2020, doi: 10.1093 / molbev / msaa119.
