The news about the infidelity gene turned out to be exaggerated

There will be no love

Alexey Timoshenko, "The Attic"

Today, the Attic will analyze the news about the "gene of female infidelity", which was reprinted by many Internet resources. The presence of this gene supposedly means that its carrier is prone to adultery so much that it is almost inevitable. In short, the verdict of the "Attic" is this: men don't have to worry.

Let's start with the statements in the press. Here is a quote from Komsomolskaya Pravda – it is quite characteristic:

"If a woman has the AVPR1A gene changed, then the partner should be ready, forgive me for the involuntary pun, for her infidelities. Sooner or later, or rather sooner, such a woman will sleep with someone else."

Everyone has the AVPR1A gene. Both men and women. A gene is a piece of DNA from which you can take a kind of impression in the form of an RNA molecule. RNA molecules are used as matrices for protein synthesis. The AVPR1A gene allows our body to synthesize one of the vasopressin receptors. Or, as biologists say, the AVPR1A gene encodes a vasopressin receptor. Vasopressin is an important hormone, and receptors are molecules by which cells interact with the hormone. Every person has vasopressin receptors.

The AVPR1A gene – like almost all other genes – occurs in humans in several variants. All variants allow cells to acquire fully functional receptors, but the structure and functions of these receptors are slightly different. You can draw an analogy with household appliances: every house has a refrigerator, but refrigerators come in different brands, different volumes and with different additional functions. To say that some variant of a gene (in the language of geneticists - "any of the alleles") is better or worse is often as difficult as answering the question: "Which refrigerator do you recommend to me?" One option is better for some cells in some conditions, another in other circumstances – another. The nerve cell in the retina of the eye and the liver cell are engaged in too different work, but the body cannot afford the luxury of keeping genes optimized for each individual task.

Like many other receptors, AVPR1A is involved in many different processes at once. If we look at how much AVPR1A is synthesized in different tissues and organs (this is called an expression diagram), we will see peaks of activity in the liver, kidneys, and also in the walls of blood vessels. All this is unlikely to have even an indirect relation to adultery. However, AVPR1A is also synthesized in the brain. Let's retell the main thing once again: most genes exist in several variants and perform several functions at once. Messages like "the Z gene responsible for X has been found" for this reason are incorrect in principle: just one of the variants of the Z gene, along with everything else, somehow affects the manifestation of X. As a rule, genes do not appear only for the sake of a single effect, this is too unprofitable from the point of view of evolution.

Taking into account the above, it is possible, without looking into a scientific article, to assume that the influence of the gene on the frequency of adultery will not be absolute, but rather probabilistic. If the article (Zietsch et al., Genetic analysis of human extrapair mating: heredity, between-sex correlation, and receptor genes for vasopressin and oxytocin) is still open, then we will learn the following: the contribution of genetic factors in extramarital affairs is estimated at about 62% for men and 40% for women. At the same time, scientists tested two previously identified genes and found out that one of them, encoding the oxytocin receptor OXTR, has nothing to do with infidelity. But one particular variant of AVPR1A was found more often in those who cheated on their partner. However, not so often that it was possible to talk about the irresistible craving of carriers of this allele for extramarital affairs.

For terminological accuracy, we define "extramarital" relationships as sex with someone without the consent of a permanent partner or partner. Since some of the studies that we are going to talk about now were done on mice or other animals, this clarification will obviously not be superfluous (although it is not clear what is meant by consent).

Vasopressin receptor gene expression diagram in different tissues (biogps.org ).
The light blue block at the bottom of the picture shows different parts of the brain.
As you can see, the gene works not only in the nervous system.

ContextThe AVPR1A gene is not being investigated for the first time in connection with its possible influence on human behavior.

Of course, there is nothing new in the very idea of the influence of hormones on our behavior: almost everyone has heard about the effect of adrenaline, as well as about the importance of iodine for mental development (iodine is part of thyroid hormones). Sleep disturbances due to a lantern under the window or after an intercontinental flight are also associated with the action of hormones, this time melatonin. A drop in testosterone levels reduces sexual desire in men, and the release of oxytocin after childbirth in parents (and both, although mothers are much more susceptible to this) increases attachment to the child. And since hormones do not act by themselves, but in conjunction with receptors, then scientists need to study both the receptors and the genes necessary for hormone production. Below you can see not even all, but only selected works on the topic. We have provided each one with a link to the original for everyone. So...

In 2007, the journal Human Mutation published a study by Australian scientists. They found that variations of the AVPR1A gene are associated with sexual behavior – there are alleles whose carriers and carriers begin sexual life somewhat earlier. And even earlier, in 2004, Twin Research presented an article by a British group that tried to find a similar connection, but did not succeed. At that time, the researchers only managed to analyze data on more than 1,600 twin sisters (there are more than seven thousand of them in the new article) and conclude that the contribution of the genetic factor to extramarital behavior at the level of about forty percent.

We emphasize that this indicator – the propensity for infidelity in women by about forty percent may be due to genes – is well consistent in two different scientific publications. But sexuality is far from the only reason to be interested in the AVPR1A gene in the context of behavior, rather than regulation of blood pressure or liver function.

In 2008, a publication appeared, the authors of which found a correlation between the presence of a certain allele AVPR1A and the style of playing "Dictator". "Dictator" is a game specially developed by economists and psychologists for two participants. One, the "dictator", receives a certain amount on his hands, after which he shares (or does not share) with his partner at his discretion. Scientists have shown that among the players who tend to take everything for themselves, there are more people with a certain variant of AVPR1A. An article with these findings is found in the journal Genes, Brain and Behavior.

At the same time, the Swedish-American group showed that alleles of the AVPR1A gene can help or hinder the formation of interpersonal contacts, and mainly in men. The findings of the scientists were published by the Proceedings of the National Academy of Sciences.

In 2010, Korean researchers found a possible link with autism and wrote an article in Neuroscience Letters.

In 2011, American psychiatrists presented data on the effect of the gene on the formation of drug addiction. An article with their arguments is presented in Biological Psychiatry.

In 2012, Canadian doctors revealed that variations in the gene of the vasopressin receptor AVPR1B – note, this is a different gene and a slightly different receptor! – associated with aggressive behavior in children. They published their findings in Psychiatry Research.

In 2013, Polish researchers found some evidence that suggests the possible influence of vasopressin AVPR1A receptors on the development of depressive disorders. These data are presented in Psychiatric Genetics. And Swedish psychiatrists have found that gene variations correlate with suicide attempts. Of course, an article for the journal Neuropsychopharmacology clarifies that the presence of a certain allele does not push people to suicide at all. In the end, such a gene, if it existed, would have been destroyed by natural selection!

In 2014, American authors showed that women (but not men) with a certain allele react more acutely to stress and are more likely to experience anger as a subsequent reaction. The article is in the Emotion magazine.

The gene has even been studied to see if it can affect the ability to sing and play music. In 2012, British scientists presented an article in PLoS One, where they honestly reported a zero result. The fact that such a connection was still found before them, the researchers explained the multifactorial nature of the process of forming a choir or musical ensemble, because people are recruited there not only for their abilities, but also taking into account psychological compatibility. It is possible that gene variations affect the ability to get along with others, and this, in turn, increases the chances of being invited to the ensemble.

We also do not write anything about the study of the role of polymorphism (another term for variability) AVPR1A in the aggressiveness of pigs or in the success of sports training in pensioners. It is enough just to say that there are such publications.

The studies we have shown support the conclusion made at the beginning. There are many genes, each has several functions, so there can be no "adultery gene" in principle. It can only be a predisposition, the contribution of which is often noticeably lower than the contribution of culture, upbringing and circumstances.

Even widerIf we return to sexual behavior, its connection – including in female mice and monkeys of different species – with the AVPR1A polymorphism has indeed been demonstrated several times.

However, such data can be transferred to a person only with very significant reservations. After all, two equidistant chimpanzee species, the common and the dwarf bonobo, exhibit very different reproductive strategies.

Bonobos are bisexual and the dominant role in the group is often played by females. Bonobos, as a rule, are a very inconvenient example of "naturalness" for those who want to justify this or that sexual behavior of people as "inherited from nature". Although these closest relatives of ours are far from the strangest, from a human point of view: they are far from even spotted hyenas, not to mention squid.

The reproductive organs of spotted hyenas have been confusing naturalists for a long time: females have a pseudopenis, which is larger than the sexual organ of males. During childbirth, newborn hyenas pass through the vagina located inside the pseudopenis. Moreover, from the point of view of anatomy, this organ is a greatly enlarged clitoris. It is not very clear yet how such an unusual anatomy is related to the structure and work of the brain, but hyenas have matriarchy in packs: the highest-ranking male is lower in position than any female.

In seahorses, the usual pattern of internal fertilization looks even more bizarre. The female places an egg inside the male, which then divides and develops inside the father's body. And some types of squid for fertilization pierce the body of females with thorns, while transferring their sperm inside. In crocodiles, biological sex is not related to genes, but is determined by the temperature regime of embryo development; cuckoos got rid of the typical bird care for offspring; in naked diggers, the burrow is organized almost like an anthill (with the main female, who alone gives offspring) – almost any "natural" pattern in sexual or parental behavior can be refuted on an example of an animal.

Genetically, humans are related to hyenas by more than 80%. With platypuses – by 69%, by 65% – with chickens, and about a quarter of the genes coincide with grapes.

So when you once again read the headline in the spirit of "experiments on mice revealed the gene of adultery," remember that such statements are at least incorrect, and at most they are completely distorting. Actually, scientists themselves almost always honestly make all the necessary reservations, which mysteriously disappear when retelling.

Numerous references to publications in scientific journals can be found in the original article – VM.

Portal "Eternal youth" http://vechnayamolodost.ru04.03.2015