Can healthy or bad habits, diet and exercise affect children or grandchildren? Whether our lack of sleep or extra glasses of champagne will backfire on our descendants - suddenly, due to our unreasonable decisions, children will show a tendency to alcoholism, diabetes or carpal tunnel syndrome?
The article below summarizes the main arguments of genetic scientists, doctors and other specialists who answered this question in the "Ask Science" section of the popular Reddit portal.
ALTHOUGH A LIFESTYLE DOESN'T AFFECT DNA STRUCTURE, IT CAN AFFECT FACTORS THAT REGULATE GENE ACTIVITY
This phenomenon is called epigenetic inheritance: depending on what factors influenced the organism during life, its offspring may or, conversely, not manifest some properties that were originally incorporated into the genetic code.
The structure of the genome itself, which is passed on to the offspring, can only be changed during pregnancy: poor nutrition, stress or diseases suffered by the mother during this period can cause mutations at the genetic level and disruption of DNA structure - for example, due to such mutations, children can be born with an extra chromosome.
But these changes are quite random, do not always occur and often are not associated with the mother's lifestyle. This is a gene abnormality that is difficult to predict before conception, but today future parents can be prevented with the help of prenatal diagnostics - the research program includes a special test that allows you to check the fetus for 6,000 possible developmental disorders.
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HOWEVER, NOT ALL PROPERTIES TRANSFERRED FROM PARENTS TO DESCENDANTS ARE INSERTED IN DNA
The mechanism of inheritance outside the structure of the genetic code is studied by a special branch of science - epigenetics. The term itself was coined by the Englishman Konrad Waddington in the 50s. The scientist did not yet know how the human genome works, but he guessed about the existence of a certain mechanism that controls the hereditary material of living beings.
In the 1990s, when human DNA was deciphered, researchers recalled epigenetics and found support for Waddington's hypotheses. Now epigenetic (literally - "overgenic") inheritance refers to all changes associated with the phenotype or gene expression that are manifested in descendants in the first generation in living beings and in several generations in cellular organisms.
SCIENTISTS DO NOT KNOW EXACTLY INHERITANCE IN LIVING BEINGS
To track the reasons for the manifestation of similar signs, you need to take into account an infinite number of factors: the conditions in which the growth and development of the animal took place, environmental factors, ecology, cosmic radiation, and so on.
Researchers cannot say for sure what affects gene expression, and if you exhibit the same properties as your parents, this does not mean that they were transmitted to you genetically. Perhaps your phenotype is influenced by the climate, the rhythm of life in your hometown, or the consumption of food that is familiar to your family.
IT IS ESPECIALLY DIFFICULT TO DESCRIBE THE MECHANISM OF INHERITANCE OF CERTAIN FEATURES AND FEATURES OF CHARACTER IN PEOPLE - unlike most animals, people in their development are strongly dependent on society, and the child in the process of growing up is influenced by his relatives, peers, teachers, film characters, characters adopted in society and orders.
Roughly speaking, if three generations of a family go in for sports, this does not mean that children inherit relief muscles genetically: first of all, they are influenced by upbringing and the family tradition of spending evenings in the gym.
But what if not only physiological characteristics, but also patterns of behavior can be passed from generation to generation? Thanks to this question, a new direction has recently appeared - behavioral epigenetics. Scientists working in this area suggest that the lifestyle of the parent organism can affect the character and behavioral scenarios of the offspring.
In 2013, the authoritative journal Neuroscience published the results of experiments carried out on laboratory mice: the researchers taught the animal to be afraid of the smell of cherries (they seem to explain nothing about the choice of flavor), and then observed the manifestation of the same fear in the offspring of this mouse and even subsequent generations …
WE CANNOT KNOW EXACTLY WHAT CAUSED THIS: perhaps the mechanism of genetic transmission of behavioral scripts is much more complex and in mice it manifests itself in a completely different way from in humans.
But biologists say that the ability to transfer acquired skills by genetic means would be a good accelerator of evolution, because in this way more perfect creatures would appear much faster than due to random gene mutations. If you believe that nature is arranged logically, the transmission of patterns of behavior would be very useful for the development of living things.
BUT ARE ALL THE BEHAVIORAL SCENARIOS PASSED TO THE DESCENDANTS, OR ONLY THOSE THAT WERE USEFUL FOR THE PARENTAL CREATURE?
Fear is a manifestation of a self-preservation instinct that helps a mouse to protect itself and the future of the population, and the habit of drinking alcohol, for example, has the exact opposite effect.
Geneticists say that the presence of several alcoholic relatives in the family tree does not increase the child's chances of becoming addicted to drinking: most likely, there will be a predisposition to alcoholism in his DNA, but without the stimulating influence of the social environment, this gene will not manifest.
IT TURNS OUT THAT THE EXPERIENCE GETTED BY THE PARENTS CAN ALLOW ANYTHING IN THE PROCESS, BUT CANNOT CHANGE DNA
Since epigenetic inheritance was discovered quite recently, researchers did not have the opportunity to trace it on several generations of people: now the phenomenon is being studied in mice, whose DNA structure is close to that of a human, and the reproduction rate makes it possible to track gene expression on parents, children and grandchildren. But the question of projecting the results of experiments on people remains open.
DOING SPORTS OR MAINTAINING THE CORRECT Eating REGIME, YOU DO NOT CHANGE YOUR GENETIC CODE, BUT USE THE OPPORTUNITIES INSERTED IN IT BY NATURE
You can compare this to game consoles: inserting different cartridges, you get different results, but without the console itself with certain technical characteristics, the cartridges mean nothing. In any case, taking care of yourself and your health is not a bad idea, even if the healthy habits developed with such difficulty are not passed on to your children epigenetically.