Neanderthal Gene Linked to Increased Fertility in Women

One in three European women carries a progesterone receptor gene--a gene inherited from Neanderthals, an ancient relative of modern day Homo sapiens. 

The study, conducted by researchers at the Max Plank Institute for Evolutionary Anthropology and the Karolinska Institutet, found that the proportion of women carrying this gene is ten times greater than any other Neanderthal gene variant. This speaks volumes on behalf of the beneficial qualities of the gene.

Progesterone Receptor Gene Came From Neanderthals

The Connection Between Progesterone and Pregnancy

Ancient Neanderthals emerged around 200,000 years ago, disappearing some 40,000 years ago. During this time, they interbred with early humans traveling through Eurasia, passing on favorable gene combinations which have survived into modern times.

Progesterone, produced by the ovaries, regulates menstruation and is key to facilitating healthy pregnancies. During the early stages of pregnancy progesterone is especially essential, although it continues to play a big part in supporting the growing fetus throughout.

Pregnant women with low progesterone are more susceptible to miscarriages as well as bleeding during their first trimester. While some believe that reducing stress and avoiding overexertion can boost progesterone during pregnancy, genes appear to be the biggest influence on progesterone production and reception.

Clearly, progesterone is important to pregnancy, suggesting that genes playing a role in progesterone receptivity would be evolutionarily beneficial. Researchers support this idea by noting the prevalence of the Neanderthal progesterone gene among modern European women. 

Twenty-nine percent of European women carry this gene, making this the most favorable Neanderthal genetic variant currently known.

By promoting fertility, this gene ensures a higher likelihood of occurrences. Because women carrying this Neanderthal gene are more likely to have children--and more likely to have more of them--the gene has a greater chance of being passed on. 

Benefits of Fertility Enhancing Gene 

Women With This Gene Have More Children, Less Miscarriages

Researchers concluded that the gene is associated with increased fertility, fewer miscarriages, less bleeding during early pregnancy, and more children. The increased production of progesterone receptors may protect against miscarriages and bleeding by raising the mother’s sensitivity to progesterone.

While progesterone sensitivity is important, there is such a thing as progesterone intolerance, which can manifest as a dermatological reaction to changes in progesterone levels. There are also women who suffer from progesterone deficiency, although current research has not yet studied the relationship between these conditions and Neanderthal gene variants.

The benefits of this fertility enhancing gene are especially impressive when brought into perspective: genetic sharing that occurred thousands of years ago in select pockets of the world population has modern day implications that could even impact fertility treatments. 

The research findings suggest ways in which this gene can enhance fertility by showing how important progesterone sensitivity is for healthy pregnancies.