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The freckle gene in question
British researchers recently developed a DNA test to detect the freckle gene in order to predict the chances of having a little redhead. But can we really know the hair color of our future baby? Why is this such a rare shade? Professor Nadem Soufir, geneticist at André Bichat hospital enlightens us …
What determines the red color of the hair?
Called MCR1 in scientific jargon, this gene is universal. However, the red hair color is the consequence of a set of variations resulting in modifications. Normally, the MCR1 gene, which is a receptor, controls the melanocytes, that is, the cells that pigment the hair. These cells make brown melanin, which is responsible for tanning. But when there are variants (there are several dozen), the MCR1 receptor is less efficient and asks melanocytes to make melanin that is yellow-orange in color. This is called pheomelanin.
It should be noted : Even if they carry the MCR1 gene, people of the African type do not have variants. They cannot therefore be redheads. Human spontaneous mutations are closely linked to his environment. This is why black people, living in regions with strong sunshine, do not have MC1R variants. There was a counter selection, which blocked the production of these variants which would have been too toxic to them.
Is it possible to predict baby’s freckles?
Today, even before conception, future parents imagine the physical criteria of their child. What nose will he have, what will his mouth be like? And British researchers recently developed a DNA test to detect the freckle gene, especially in expectant mothers in order to predict the chances of having a little redhead and to prepare for them. any medical specificities of these children. And for good reason, you can be a carrier of this gene, without being red yourself. Nevertheless the geneticist Nadem Soufir is categorical: this examination is a real absurdity. “To be red, you have to have two RHC (red hair color) type variants. If both parents are red, it’s obvious, so will the baby. Two dark-haired people can also have a red-haired child, if each of them has an RHC variant, but the odds are only 25%. In addition, the child of a mestizo or a Creole and a person of the Caucasian type may also be red-haired. “The genetics of pigmentation are complex, several factors, of which we are not yet aware, come into play.” Beyond the question of reliability, theThe geneticist denounces an ethical risk: selective abortion.
As they grow older, Baby’s hair sometimes changes color. We also observe changes during the transition to adolescence, then to adulthood. These modifications are mainly linked to interactions with the environment. For example, in the sun, hair turns blond. Red-haired children may darken as they grow older, but the tint usually remains present.
Why so little red?
If we are carriers of the freckle gene, it is very surprising that only 5% of French people are red. In addition, since 2011, the Danish Cryos sperm bank no longer accepts red donors, the supply being too high in relation to the demand. The majority of recipients indeed come from Greece, Italy or Spain and plebiscite the brown donors. However, redheads are not doomed to disappear, as some rumors advance. “Their low concentration is mainly linked to the mixing of populations. In France, thepeople of African origin, North African, who have no or very few MC1R variants, are quite numerous. However, redheads are very present in certain regions, such as Brittany where their number remains stable. “We also observe a red influence near the Lorraine and Alsatian border,” explains Dr. Soufir. In addition, there is a whole palette of red, ranging from auburn to dark chestnut. Moreover, those who call themselves Venetian blond are redheads who ignore each other ”.
With 13% red in its population, Scotland holds the record for redheads. They are 10% in Ireland.
Protect the health of red babies
Red baby: watch out for sunburn!
Sunscreen, going out in the shade, hat… in summer, one watchword: avoid exposing Baby to the sun. Parents with red-haired children should be extra vigilant. And for good reason, in adulthood, they are more likely to be affected by skin cancer, hence the importance of protecting them, from an early age, against ultraviolet rays.
For their part, Asians have a different pigmentation, and very few variants. They are therefore less likely to develop melanoma. Métis or Creoles with freckles should also be careful with the sun, even if they are certainly “better protected from the sun than whites”.
Even if redheads are predisposed to contract certain cancers and experience earlier aging of the skin, the geneticist explains that “a genetic factor that is harmful to one point also has beneficial effects”. Indeed, thePeople with MC1R variants more easily capture ultraviolet radiation in high latitudes, important for vitamin D. “This could explain why, according to the well-known principle of natural selection, Neanderthals, found in Eastern Europe, already had red hair.
A link with Parkinson’s disease?
A link between Parkinson’s disease and being red is sometimes mentioned. Nevertheless Nadem Soufir remains cautious: “this has not been confirmed. On the other hand, there is an epidemiological association between this disease and melanoma. People who have had this form of skin cancer are 2 to 3 times more likely to have Parkinson’s disease. And those who develop this disease have an increased risk of developing melanoma. There are surely links but it does not necessarily go through the MC1R gene ”. Furthermore, there is no correlation between freckles and albinism. In this regard, “a recent study carried out in the laboratory has shown that albino mice do not develop melanoma, despite their absence of pigment in the skin, unlike red mice. “
Redheads, less sensitive to pain
The invincible redheads? You could almost believe it! Indeed, the MC1R gene is expressed in the immune system and in the central nervous system giving the benefit to redheads of being more resistant to pain.
Another significant benefit: sex appeal. Redheads would be more… sexy.
Do you want to talk about it between parents? To give your opinion, to bring your testimony? We meet on https://forum.parents.fr.