According to a new study, women who inherited a variant of gene from the Neanderthals have better fertility. They also have fewer miscarriages and lower incidence of bleeding early in pregnancy.
Researchers said that a third of women in Europe carry a gene from ancient Neanderthals that codes for progesterone, making for improved fertility. Their findings appeared in the journal Molecular Biology and Evolution.
The study was done by researchers at the Karolinska Institute, Sweden and the Planck Institute for Evolutionary Anthropology, Germany.
This research provides a possible explanation as to why some women appear luckier with child-bearing than others.
“The progesterone receptor is an example of how favorable genetic variants that were introduced into modern humans by mixing with Neandertals can have effects in people living today,” said lead author Hugo Zeberg, a neuroscience researcher at the Max Planck Institute for Evolutionary Anthropology and Karolinska Institutet.
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Neanderthals were ancient relatives of modern humans. They are believed to have emerged 200,000 years ago, or earlier, and existed in Eurasia until around 40,000 years ago. Experts say they had a stronger build and shorter limbs in comparison to humans existing today.
Modern humans are thought to have interbred with the Neanderthals, who are now extinct, while migrating through Eurasia.
Progesterone and fertility
Produced by ovary’s corpus luteum, progesterone plays a vital role in the ability of a woman to bear children. It is also a factor in the regulation of the menstrual cycle.
This hormone of the progestogen group helps to preserve the baby in the womb survives until it is born. The importance of the substance is especially greater during the early stages of pregnancy.
The endometrial lining of the womb is enriched every month through the activity of progesterone. It puts the uterus in a state good enough for accepting and nurturing a fertilized ovum.
The levels of the sex hormone are usually higher while a woman is pregnant. Its production by the placenta rises during the period of pregnancy to ensure the health of the fetus until delivery.
Pregnant women who have low progesterone levels are at a greater risk of having miscarriages. They may also experience more bleeding during the first trimester.
With the aid of the Gene ATLAS tool, the team in this study analyzed the data of over 450,000 people. The data came from the UK Biobank. More than half of these subjects – specifically, about 244,000 – were women.
Analyses carried out showed that nearly a third of European women inherited the gene from Neanderthals that helps fertility. Researchers found that 29 percent of the women had a copy of the progesterone receptor. Three percent features two copies.
Zeberg said that the observed share of women having the Neanderthal progesterone gene was roughly “ten times greater than for most Neanderthal gene variants.”
The researchers said their findings were suggestive of how the progesterone receptor from Neanderthals can boost fertility.
The team discovered that women having the gene in focus tend to get pregnant more and have more children. They had lesser bleeding issues during pregnancy.
Women carrying the Neanderthal gene variant suffer fewer miscarriages. Molecular analyses revealed that these women showed more progesterone receptors in the cells, thus boosting sensitivity to the hormone and helping to avert miscarriages.