MOSCOW, November 9, Salma Sultanova. There is more and more evidence that genes encode not only appearance and susceptibility to disease, but also preferences and behavior. Scientists are even attempting to predict eating habits using DNA. How great is the influence of heredity on a person’s character – in the material .
In 1939, twins Jim Springer and Jim Lewis were born in Piqua, Ohio. The babies were given up for adoption, they ended up in different families and grew up separately, unaware of each other's existence. An unexpected meeting occurred only in 1979, when the brothers were already forty.
After communicating in person, the twins discovered that, apart from their appearance, their lives had a suspiciously lot in common. For example, they both suffer from migraines, drive a blue Chevrolet, smoke the same brand of cigarettes, and prefer Miller Lite beer. The brothers are 180 centimeters tall, weigh about 80 kilograms, and their voices are indistinguishable. As children, both went on vacation to Florida and had dogs named Toy. Having grown up, they married women with the same name Linda. Both were accustomed to leaving love notes for their spouses. Later, however, the brothers divorced the Lindas and remarried. On two Bettys. There were other similarities, including career ones.
The story of the amazing similarity of twins who grew up separately attracted the attention of University of Minnesota psychologist Thomas Bouchard Jr.
“I remember our first meeting. Then we sat down at the table, and I noticed that both of their nails were completely bitten off. I thought: “Not a single psychologist asks about this, but here it is, staring you in the face,” said Bouchard.< br />Acquaintance with Jim Springer and Jim Lewis inspired the scientist and his colleagues to researchother twins separated in infancy. Experts wanted to find out whether the phenomenon of two Jims was isolated or whether everyone, regardless of the circumstances, had similar habits and preferences. More than a hundred pairs of identical and fraternal brothers and sisters were selected from different countries to participate in the experiment. There were also triplets. They had to undergo medical and psychological tests, including an IQ test, talk to a psychiatrist, and talk in detail about their life history.
Identical twins had the most similar answers. Particularly striking were the IQ results, which were practically no different from those shown by couples who grew up together. The authors concluded that the reason is an identical genome.
How genes choose for us
Over time, the hypothesis that some individual tendencies depend on heredity , found more and more confirmation. Thus, in 2014, physician and sociologist from Yale University Nicholas Christakis and professor of medical genetics and political science at the University of California at San Diego James Fowler demonstratedthat genes can tell us who to make friends with. Turning to data from a large heart study, the Framingham Heart Study, experts selected 1932 people, most of whom had friendly connections with each other. An analysis of almost five hundred thousand genetic markers showed that friends share gene variants more often than strangers.
“Your friends don’t just look like you in appearance, they look like you genetically,” he said in an interview with The Guardian Nicholas Christakis.
“The similarity is insignificant, only about a percentage of genetic markers, but its significance for evolutionary theory is great,” noted James Fowler.
Similar results were later obtained by scientists from the USA: they discovered that for the manifestation of friendly feelings The enzyme phosphodiesterase PDE11A4, expressed in the hippocampus of the brain, may respond. Observation of animals helped to reach this conclusion – they were much more reluctant to communicate with relatives in whom the gene responsible for the production of this enzyme was disabled.
Some scientists believe that we also choose romantic partners for a reason. There is an assumption that we are attracted to people of the same height as us. It is not yet clear what determines such sympathy to a greater extent – genetic factors or the environment. We tried to answer this questionresearchers from the University of Edinburgh. They involved more than 13 thousand couples from the UK in the study. After analyzing their genotypes, the authors came to the conclusion that the same genes that shape our own height are responsible for choosing a partner. That is, a tall person is likely to prefer someone equally tall and vice versa.
In work publishedScientific Reports shows that we also choose educational subjects for a reason. Using data from the world's largest cohort study of twin development, Twins Early Development, the authors looked at what subjects 6,584 sibling pairs enrolled in when entering their A-Level programme. It turned out that the decision to choose one course or another is 80 percent determined by heredity. At the same time, scientists estimated the influence of the environment, for example, at school or at home, at a modest 23 percent.
Other studies show that sleep-wake patterns are also determined genetically. Thus, an international group of researchers, having analyzed the genomes of almost seven hundred thousand people, found genetic variants that regulate circadian rhythms. For example, “larks” are characterized by 351 DNA sections.
“We don't really have a preference for a particular regimen. However, nature takes its course, and we end up in either one category or the other,” Michael Weedon, an associate professor at the University of Exeter Medical School in the UK and a co-author of the study, told CNN.
Meanwhile last year an article was published in PLOS Biologythat love for nature is also inherited. A survey of 1,153 pairs of twins showed that identical twins, whose genes are almost one hundred percent identical, have a similar attitude towards spending time outdoors and travel out of town with the same frequency. At the same time, the answers of fraternal twins, whose genetic material is only half similar, differed more widely. The authors calculated that heredity forms a craving for nature by 46 percent.
Research in neuroscience and psychology suggests that morality, the brain's ability to distinguish right from wrong, is a product of evolution. Psychologists from the University of Edinburgh Michael Zakharin and Timothy Bates wanted whether it could be inherited. By combining two independent studies on twins, scientists concluded that genes significantly influence our moral principles.
However, medical practitioners have a different opinion.
“Of course, certain genetic predispositions, combined with lifestyle, eating habits, sleep patterns and the amount of physical activity, can influence our achievements, health status, physical capabilities and food preferences, but this influence is minimal,” says a member of the Association of Medical Genetics ” and the “Russian Association of Human Reproduction”, geneticist at the Center for Reproduction and Family Planning “Life Line” Yulia Zinovieva.
The same applies to negative behavior. According to the specialist, one should not forget about the importance of the environment in which a person is brought up. Bad habits and maladaptive behavior can be a consequence of the example that adult family members set for the child. Psychological trauma has a great impact – they often influence the choice of life path.