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What do children inherit from their parents? Genes: meaning, influence, transmission to descendants, genetic diseases.

Text: Evgenia Keda, consultant - Alexander Kim, Doctor of Biological Sciences, Honored Professor of Moscow State University

One day, the famous English writer Bernard Shaw was approached with an unusual request - a fan urged him ... to make her a child. “Just imagine, the baby will be as beautiful as me and as smart as you!” she dreamed. “Madame,” Shaw sighed, “what if it turns out the other way around?”

Of course, this is a historical anecdote. But surely modern science can predict with a high probability what exactly is inherited from parents, what a son or daughter will inherit - the ability to do mathematics or music.

What is inherited: the role of chromosomes

From the school curriculum in biology, we remember exactly that the sex of the child is determined by the man. If the egg is fertilized by a sperm carrying the X chromosome, a girl is born, if the Y chromosome is a boy.

It has been proven that X chromosomes carry genes that are more responsible for appearance: the shape of the eyebrows, facial contours, skin and hair color. Therefore, it is logical to assume that boys with one such chromosome are more likely to inherit their mother's appearance. But girls who received it from both parents can equally be similar to both their mother and father.

Expert comment: “Actually, the X chromosome that boys get is just one of 46 in the genetic code. And in all 46 chromosomes there are genes responsible for a variety of traits. So boys don't necessarily look like their mother."

! most likely to be transmittedby inheritance: height, weight, fingerprints, predisposition to depression.

! With a low probability of being transmittedby inheritance: shyness, temperament, memory, eating habits.

What is inherited: does the strong win?

In the same textbook it is clearly written: genes are divided into dominant (strong) and recessive (weak). And every person equally has both.

For example, the brown-eyed gene is dominant and the light-eyed gene is recessive. Brown-eyed parents are more likely to have the same dark-eyed child. However, one should not think that the appearance of a blue-eyed descendant in such a family is completely excluded. Both mom and dad can carry the recessive light-eyed gene and pass it on at the time of conception. Chances are, of course, small, but they are. Moreover, not one gene, but a whole group, is responsible for each trait on the part of the parent, and the combinations here are multivariate.

Strong, most often inherited genes include dark and curly hair, large facial features, a massive chin, a hooked nose, and short fingers. For two blonds, the little one is likely to be blond. But the brunette and the blond have dark blond (the average color between mom and dad). Sometimes, quite unexpectedly, the traits of distant relatives are inherited by the child. There is nothing surprising in this; probably, in previous generations, these genes lost in an unequal struggle, but here they turned out to be dominant and won.

Does the baby look nothing like you? Take a closer look. Perhaps he has your facial expressions: he also wrinkles his forehead when he thinks, protrudes his lip when he is offended. Tell me, is he copying you? Yes and no. It has been observed that blind children who have never seen their relatives nevertheless quite accurately repeat their gestures and facial expressions.
Probably, many have noticed that the same parents have the first child - the spitting image of dad, the second - unusually similar to mom, and the third - a copy of grandfather. In this case, we are talking about the splitting of genes. The environment and family are the same, but the combinations of genes received by siblings are completely different.

Expert comment:“Parents themselves are unlikely to be able to figure out what will be inherited by the child. It is not at all necessary that dark-haired mothers and fathers will have the same dark-haired child, and fair-haired - fair-haired. In this case, the genealogy of a person, the history of ancestors on both sides, has a great influence. A specialist geneticist will help to figure it out, but he will also have to seriously delve into the family tree. ”

What is inherited: the appearance of the child

Growth is also difficult to predict. If the parents are very tall, the baby, most likely, will also reach the Kolomna verst. Dad is big and mom is petite? The child will probably stop at the average. However, proper baby food, and sufficient sleep for the child, and active sports, and even the climate have a great influence.

Scientists believe that intellectual abilities are 50–70% determined by genes, and the choice of profession is 40%. At 34%, we have a tendency to be polite and rude. Even the desire to sit in front of the TV for a long time is 45% a genetic predisposition. The rest, according to experts, is determined by upbringing, social environment and sudden blows of fate - for example, diseases.

A gene, just like an individual organism, is subject to natural selection. If, for example, it allows a person to survive in harsher climates or to endure physical activity longer, it will spread. If, on the contrary, it provides the appearance of some harmful trait, then the prevalence of such a gene in the population will fall.

During the fetal development of a child, this influence of natural selection on individual genes can manifest itself in a rather strange way. For example, genes inherited from the father are "interested" in the rapid growth of the fetus - since the paternal organism obviously does not lose from this, and the child grows faster. Maternal genes, on the other hand, promote slower development—which ends up taking longer, but leaving the mother with more energy.

Prader-Willi syndrome is an example of what happens when mom's genes "win". During pregnancy, the fetus is inactive; after birth, the child has a developmental delay, a tendency to obesity, short stature, drowsiness and impaired coordination of movements. It may seem strange that these apparently unfavorable traits are encoded by maternal genes - but it must be remembered that normally the same genes compete with paternal ones.

In turn, the “victory” of paternal genes leads to the development of another disease: Angelman syndrome. In this case, the child develops hyperactivity, often epilepsy and delayed speech development. Sometimes the patient's vocabulary is limited to just a few words, and even in this case the child understands most of what is said to him - it is the ability to express his thoughts that suffers.

Of course, it is impossible to predict the appearance of the child. But you can say with a certain degree of certainty what the main features will be. Dominant (strong) and recessive (weak) genes will help us with this.

For each of its external and internal characteristics, the child receives two genes. These genes may be the same (tall, full lips) or different (tall and short, plump and thin). If the genes match, there will be no conflict, and the child inherits full lips and tall stature. Otherwise, the strongest gene wins.

A strong gene is called dominant, and a weak gene is called recessive. Strong genes in humans include dark and curly hair; baldness in men; brown or green eyes; normally pigmented skin. Recessive traits include blue eyes, straight, blond or red hair, and lack of skin pigment.

When a strong and a weak gene meet, the strong one usually wins. For example, mom is brown-eyed brunette, and dad is blond with blue eyes, with a high degree of probability we can say that the baby will be born with dark hair and brown eyes.

True, brown-eyed parents may have a newborn with blue eyes. Thus, the genes received from the grandmother or the grandfather could affect. The opposite situation is also possible. The explanation is that it turns out that not one gene from each parent, as was previously believed, is responsible for any trait, but a whole group of genes. And sometimes one gene is responsible for several functions at once. So a number of genes are responsible for the color of the eyes, which each time are combined in a different way.

Hereditary diseases transmitted by genes

A baby can inherit from his parents not only appearance and character traits, but also diseases (cardiovascular, oncological, diabetes, Alzheimer's and Parkinson's).

The disease may not manifest itself if elementary safety measures are taken. Tell the gynecologist in detail about serious health problems not only for you and your husband, but also for close relatives. This will help protect the baby in the future. Sometimes completely healthy parents give birth to a baby with a hereditary disease. It was laid down in the genes and manifested itself only in the child. This usually happens when both parents have the same disease in their genes. Therefore, if a child is planned, according to experts, it is better to undergo a genetic examination. This is especially true of a family in which children with hereditary diseases were already born.

A weak gene may not be detected in one or many generations until two recessive genes from each parent meet. And then, for example, such a rare sign as albinism may appear.

Chromosomes are also responsible for the sex of the child. For a woman, the chances of giving birth to a girl or a boy are equal. The sex of the child depends only on the father. If an egg meets a sperm with an X sex chromosome, it will be a girl. If U - a boy will be born.

What else can depend on genes:

Gender - 100%;

Height - 80% (for men) and 70% (for women);

Blood pressure - 45%;

Snoring - 42%;

Female infidelity - 41%;

Spirituality - 40%;

Religiosity - 10%.

There are also genes responsible for the development of certain conditions, such as depression or a tendency to uncontrolled eating.

The level of mutations in men is 2 times higher than in women. Thus, it turns out that humanity owes its progress to men.

All representatives of the human race are 99.9% identical in DNA, which completely sweeps aside any basis for racism.

The life of each person begins with the fusion of two germ cells, maternal and paternal gametes containing chromosomes. Chromosomes carry genes, and each of them is its own set, they are redistributed randomly, forming new combinations. This is how we are different from each other!

A modern American researcher, one of the leading experts in the field of behavioral genetics, Robert Plomin, claims that each of us is a unique genetic experiment that will never be repeated. Even the chance that children of the same parents will get the same set of genes is one chance in 64 trillion possibilities. The exception is twins, but even there there is no one hundred percent match in the genetic set.

Not so long ago, there was an opinion that health is transmitted through the maternal line, and intelligence through the paternal line, but the inquisitive minds of scientists did not stop at research. And here are some interesting conclusions they got: it is proved that among women the average level of intelligence prevails, and among men there are often deviations in both directions. Why is this happening?

It turns out that scientists conducted the first large-scale genetic study in this regard and came to the conclusion that the power of intelligence is inherited through the mother's line, and not the father, as previously thought.

SO THE GENDER STEREOTYPES THAT EXISTED FOR LONG CENTURIES NOW HAVE TO DISAPPEAR.

It is the mother's genes, as it turns out, that are directly responsible for the development of the cerebral cortex, and the father's - for the development of the limbic system. In other words, you took intellect from your mother, and your typical emotional state from your father.

Moreover, some other studies have shown that people inherit their mother's intelligence because intelligence genes are located on the X chromosome.

The genes that “transmit” the gifts of intelligence by inheritance are located on the X chromosomes. Women have two such chromosomes (XX), and men have only one (XY), so the genes responsible for intelligence are more active in women, and a genius dad can pass on his high IQ to his daughter, but not to his son.

Intelligence is transmitted along the X chromosome. If a daughter is born, then the intellect from the genius-father will definitely be transferred to her genes along with the same X chromosome that determines her sex. After all, she will have two X chromosomes: one is paternal, and the second is one of the maternal. Therefore, the sons who have shown remarkable abilities and talents are only obliged to their mother for this gift!

But there are other factors

Recently, researchers at the University of Ulm in Germany found that genetics is not the only reason for high intelligence. Whether you are smart or not is also influenced by other factors.

The main additional factor is the degree of attachment to the mother, especially before the age of two. Children who regularly played complex games with them that required character recognition later grew up to be smarter adults than most of their peers.

The second factor is love. If the emotional needs of children under the age of 13 were almost completely met, 10% more cells formed in their hippocampus than those who were emotionally distant from their mother.

Will the daughter get her father's rare hair? To get answers to these questions, you can go to the soothsayer Baba Inge or peer into the coffee grounds. However, instead of engaging in shamanism, it is better to remember the school biology course.

While you were exchanging notes with your best friend or counting crows while looking out the window, the teacher patiently explained to you and your classmates what happens when female and male germ cells unite. In the process of merging, a new life appears, which receives part of the paternal and maternal genes that carry a huge amount of information: they are responsible for the appearance, health, mental abilities of the unborn child. Despite the fact that the baby receives all the signs from mom and dad, he is born a completely unique personality, whose exact portrait cannot be drawn by any scientist in the world: no one knows for sure how the genes will intertwine in a bizarre way. However, there are a number of features that can be predicted with a certain degree of probability: for example, what will be the color of the child's eyes, shade of hair, height, etc.

Exact copy?

Surely you have heard the popular belief more than once that girls are born like dads, and boys, on the contrary, become copies of their mothers. This theory is only partly true: it is believed that the genes responsible for the shape of the face, the shape of the cheekbones and eyebrows, smile, etc., for the most part, live on the X chromosome. At the same time, the boys receive it from their mother, and from their father they get the U sex chromosome, which is rather poor in external signs. Therefore, peanuts are really more often obtained by "mother's sons." As for girls, they inherit two X chromosomes from both parents at the same time. So it’s impossible to say who the little princess will look like: she has an equal chance of getting both mom’s and dad’s face.

Pansies

In moments of the highest tenderness, the husband whispers with rapture in your ear: "Our daughter will have your blue eyes, like the spring sky." If at the same time your spouse has brown eyes, you will have to upset him: the probability of having a light-eyed baby is negligible. The fact is that genes are recessive or dominant. In this case, the dark color of the iris is strong, and blue, however, like gray and green, is weak, which surrenders under the powerful pressure of the first. Your chances of producing a blue-eyed girl are 25%, black-eyed beauty - 75%. But if your husband, like you, has a blue iris, you will never have a child with dark eyes. But two brown-eyed parents can expect a surprise: there is a 25% chance that the baby will hit mom and dad with an unexpected blue eye color.

Curly Sue

Light hair color, like blue eyes, is considered a recessive trait. That is why some publications periodically publish articles on the topic that someday there will not be a single blond on planet Earth: they will be absorbed by stronger brunettes. However, the World Health Organization does not get tired of refuting this dubious information: recessive genes do not disappear without a trace, but are passed on from generation to generation to ever appear again. However, this does not mean at all that your wheaten hair color will go to children, it is quite possible that it will appear in grandchildren or great-grandchildren. Here, as in the case of the eyes: a pair of "blonde plus brunette" has only one chance in four to give birth to goldilocks. The same applies to saffron milk caps: chestnut curls, alas, are recessive. But if you are a happy owner of a lush, curly mop of hair, with a high degree of probability you will get a baby whose head will be decorated with charming curls. Because curly curls are dominant, and straight ones are recessive.

Dimples and humps

On the first date with your faithful, you were smitten on the spot by his noble Roman profile - a hooked nose - and a sexy dimple on his chin. Keep in mind, your future son has every chance of becoming a sultry heartthrob: some scientists believe that the genes responsible for these traits are dominant. Unfortunately, these same experts also consider lop-earedness to be a very strong trait that is inherited. So, if someone in your family boasts funny ears, the child will get them as a dowry.

Gulliver and Thumbelina

Some men are crazy about girls of model dimensions with a height of at least 175 cm, others prefer miniature Thumbelinas. Ladies, unfortunately, are more categorical: tall machos are valued in modern society (shorty Tom Cruise is an exception to the rule, after all, a too pretty face compensates for his short stature). Therefore, most likely, you dream of a giant son, whose charms not a single beauty can resist. Alas, predicting the growth of an unborn baby is a very difficult task. After all, it is influenced not only by the parameters of the parents, but also by lifestyle, nutrition, past illnesses. However, there is a high probability that tall moms and dads will have children to match them. However, parents with modest dimensions in the presence of tall grandparents can count on the fact that the child will outgrow them themselves.

By the way, if you have free time and you are ready to do simple calculations, you can try to calculate the growth of your future child using special formulas. A certain Czech researcher V. Karkus is sure that the height of a girl should be calculated according to the following scheme: multiply the parameters of the father by 0.923, add the height of the mother and divide by 2. For the dimensions of the boy, you will need a different formula: add the height of mom and dad, multiply by 1.08 , divide by 2. For example, if your partner is 185 cm and you are 170 cm, then, according to the Karkus formulas, your son will grow to approximately 192 cm, and your daughter will be your height.

mind for mind

You graduated from high school with a gold medal, college with honors, and your husband was saved from the army only by his family's personal acquaintance with the rector of the university. Fortunately, your children most likely will not follow the path of a slob father. According to recent studies, intellectual abilities are more transferred from mom than from dad. However, a brilliant man can also reward his offspring with a remarkable mind, but only if he gives birth to a girl and provides her with his X chromosome. Unfortunately, this does not apply to the game that the boy will receive.

Children to order

Who will be born to you, a boy or a girl, depends on which father's cell merged with mother's to give rise to a new life. One half of the paternal gametes contains the X chromosome, the other half contains the U. The fusion of the first with the mother's egg leads to the birth of a little princess, the second - a tomboy. However, this information became known to people relatively recently. Our ancestors were sure that other factors influence the sex of the child.

China: head north. The ancient Chinese believed that in order for an heir to be born, a woman during lovemaking should lie with her head to the north, to conceive a girl - to the south.

Germany: rain for girls. German great-great-grandmothers were sure that if you make love during the rain, then a girl will certainly be born, and dry weather contributes to the appearance of males.

Greece: love in the heat. The ancient Greek philosopher and physician Empedocles believed that in hot weather there are much more chances to conceive a male baby, and in the cold season, respectively, a female.

Tibet: even-odd. There was a belief in Tibet: if parents dream of an heir, they should conceive him on an even day. Those who dream of a girl should move their lovemaking to the odd one.

People of the future

Since people discovered the science called "genetics", they have been haunted by the thought of what the person of the future will look like. The researchers are divided into two camps: the adherents of the first are sure that we will be reborn into gigantic beauties, the representatives of the second are prophesying an ugly future for us.

Bold beauties. Medicine will be more and more improved, which means that human life expectancy will increase to 120 years. At the same time, there will be no early aging: at 80 we will look forty. Compared to past centuries, we have already grown significantly, this trend will continue, and the man of the future will eventually begin to look at the world from a height of two meters. Races will disappear: earthlings will all become swarthy and very beautiful. Facial features will be more symmetrical, bodies will be athletic, eyes will be large and clear.

Three-toed goblins. The habit of chewing lighter and lighter food will make a person's face childishly round, and his teeth rare and small. In the process of mutations (for several thousand years people have already lost three-quarters of their sense of smell), our nose will fall off, from which two small holes will remain. To make it easier to press the keys, the fingers will become long and thin. Over time, there will be three of them on each hand. The need to contain a huge amount of information will lead to the fact that the brain will grow to an incredible size, because of which the human head will become large and round. Under the influence of environmental factors, growth will decrease by almost half a meter, muscle mass will decrease, hair will disappear from our bodies, and the skin will coarsen. The abundance of dirt and dust in the air will make a person's eyes slanted and provide them with a protective dark film.

Stars about genes

Olga Budina:

There are children who become copies of their parents. I can’t say the same about my son: he doesn’t look like me like two drops of water. However, it is impossible not to notice some of my features, which were repeated in Naum with amazing accuracy.

Firstly, he has my facial expressions: he smiles, says, frowns, laughs exactly like a mother. Secondly, the son is amazingly musical. Thirdly, at the age of five he is already a perfectionist and very ambitious.

Valeria:

All musicians in my family. Grandparents, although they were not professional artists, played the piano. My children inherited this trait: they have a penchant for music, but I do not see the desire for it in them. Although the eldest son studied piano and clarinet, the daughter plays the piano, the youngest went to a music school at the age of four. The teachers called him gifted and said that he was “their” child and needed to be developed.

Incredible Facts

Parents love to pretend What will their future child look like?.

Will he inherit his mother's eyes or his father's nose? Are there certain traits we get from each parent?

Genetics is an interesting and very complex thing. A child receives 23 chromosomes from the mother and 23 from the father, and there are many options for how they will be combined and what the end result will be.

Although the genetic influence is generally equal on the part of both parents, many scientists conclude that father is sometimes more influential than mother.

1. Eye color

Dark eye colors such as brown and black are dominant, while light eye colors such as blue are recessive.

Usually the child inherits the dominant eye color of the parents. For example, if dad has brown eyes and mom has blue eyes, then the child is likely to be brown-eyed.

But this is not always the case. If the father has a recessive eye color, such as blue or green, the child is more likely to inherit the father's eye color.

2. Dimples on the cheeks

What could be cuter than dimples, and if your father had dimples, chances are high that the child will be born with the same cute dimples.

Cheek dimples are a dominant feature, and their appearance is associated with the location of the muscles on the face.

3. Fingerprint pattern

Each person has their own unique fingerprints, and they are not repeated in parents and children. However, there is a genetic predisposition towards fingerprints.

The prints of fathers and children, though never the same, are very similar. Look at the hands of a child and you will see similar curls or arches in the father.

4. Symmetry of the face

Genetics play a big role in what facial features or the ratio of these traits your children will have.

Children tend to inherit the facial symmetry of the father and if, looking at your son or daughter, you clearly see his father, then there is a reason for this.

5. Child growth

The growth of the child is influenced by the genes of both parents, however father plays a big role in how tall or short a child will be. If the father is tall, then the children will also be tall, maybe not as tall as the father, if the mother is short, but nonetheless.

6. Baby's weight

Weight is largely determined by genetics, and there is a relationship between the weight of the parents, especially the father, and the weight of the children when they grow up.

It's interesting that father's weight may affect birth weight of baby. So, if the father's genes are expressed during pregnancy and intrauterine development of the child, then the mother's genes can be suppressed to some extent.

7. Hair

As with the eyes, dominant and recessive genes have a big impact on hair color.

Dark hair is dominant, and if your father has dark hair, then yours is likely to be dark too.

Moreover, the father's genes play a decisive role in what will be the texture of the baby's hair. If the father has curly hair, then it is unlikely that the child will have straight hair.

8. Lips

As for the shape and size of the lips, the father's genes can significantly affect this trait. Full lips are a dominant feature, and if the father has full lips, then the child is also likely to have full lips.

9. Dental problems

Unfortunately or fortunately, the structure of the teeth, as well as the problems associated with them, is a hereditary trait. If the father had bad teeth, then the child will probably have to face problems too.

Did you know that there is gene responsible for gaps between teeth? If your father had a gap between his teeth, don't be surprised if you inherit one.

10. Risk-taking

If a father likes to take risks, then this can leave an imprint on the personality of future children. It is believed that a person's personality is to some extent predetermined from birth.

So, for example, there is a gene responsible for the search for novelty and inclining a person to risky behavior. A person who is adventurous most likely inherited this feature from his father.