Genetics is not only an interesting science, but also convenient. Researches of scientists have proved that a lot of us do not depend on us, but inherited. Genes, it can't be helped.
Dominant and recessive
It's no secret that our appearance is made up of a number of features that are determined by heredity. You can talk about the color of the skin, hair, eyes, height, physique, and so on.
Most genes have two or more variations, called alleles. They can be dominant and receptive.
The complete dominance of one allele is extremely rare, including due to the indirect influence of other genes. Also, the appearance of the baby is affected by multiple allelism observed in a number of genes.
Therefore, scientists only talk about a higher probability of the appearance in children of external signs caused by the dominant alleles of the parents, but nothing more.
For example, dark hair color is dominant over light hair. If both parents have black or light brown hair, then the child will have dark hair.
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Exceptions are possible in rare cases if there were, for example, blondes in the family from both parents. If both parents have blond hair, then the likelihood that the baby will be a brunette increases. Curly hair is more likely to be inherited because it is dominant. As for eye color, dark colors are also strong: black, brown, dark green.
Features such as dimples on the cheeks or chin dominate. In a union where at least one partner has dimples, they are likely to be passed on to the younger generation. Almost all of the prominent features of appearance are strong. It can be a large, long nose or a hump on it, protruding ears, thick eyebrows, puffy lips.
Will the girl be obedient?
Whether the daughter will become a neat girl who loves dolls, or will grow up like a boy, playing "Cossack robbers" is largely determined by the maternal instinct, which, as it turned out, depends on two genes.
Research conducted by the Human Genom Organization (HUGO) shocked the scientific community when it presented evidence that the maternity instinct is transmitted exclusively through the male line. That is why scientists argue that girls are more likely to resemble paternal grandmothers than their own mothers in terms of behavior.
Inherited aggressiveness
In the Human Genome project, Russian scientists were tasked with determining whether aggressiveness, irritability, activity and sociability are genetically inherited traits, or are formed in the process of education. We studied the behavior of twin children aged 7 to 12 months and their genetic relationship with the type of parental behavior.
It turned out that the first three traits of temperament are hereditary, but sociability is formed by 90% in the social environment. For example, if one of the parents is prone to aggression, then with a probability of 94% this will happen again in the baby.
Alpine genes
Genetics can explain not only external signs, but even the national characteristics of different peoples. So, in the genome of Sherpas there is an allele of the EPAS1 gene, which increases the presence of hemoglobin in the blood, which explains their adaptability to life in high mountain conditions. No other people have this adaptation, but exactly the same allele is found in the genome of the Denisovans - people who do not belong either to Neanderthals or to the species Homo Sapiens. Probably, many millennia ago, Denisovans interbred with the common ancestors of the Chinese and Sherpas. Subsequently, the Chinese living on the plains lost this allele as unnecessary, but the Sherpas retained it.
Genes, sulfur and sweat
Genes are even responsible for how much a person sweats and what kind of earwax he has. There are two versions of the ABCC11 gene that are common in the human population. Those of us who own at least one of two copies of the dominant version of the gene produce liquid earwax, while those with two copies of the recessive version of the gene have hard earwax. Also, the ABCC11 gene is responsible for the production of proteins that remove sweat from the pores in the armpits. People with hard earwax do not produce such sweat, so they have no problems with smell and the need to constantly use deodorant.
Sleep gene
The average person sleeps 7-8 hours a day, but if there is a mutation in the hDEC2 gene that regulates the sleep-wake cycle, the need for sleep can be reduced to 4 hours. Carriers of this mutation often achieve more in life and career due to the extra time.
Speech gene
The FOXP2 gene plays an important role in the formation of the speech apparatus in humans. When this was found out, geneticists conducted an experiment to introduce the FOXP2 gene in chimpanzees, in the hope that the monkey would speak. But nothing of the kind happened - the zone responsible for the functions of speech in humans, in chimpanzees, regulates the vestibular apparatus. The ability to climb trees in the course of evolution for the monkey turned out to be much more important than the development of verbal communication skills.
Happiness gene
For the past decade, genetics has been struggling to prove that a happy life requires the appropriate genes, or rather, the so-called 5-HTTLPR gene, which is responsible for the transport of serotonin (the "happiness hormone").
In the last century, this theory would have been considered insane, but today, when the genes responsible for baldness, longevity or falling in love have already been discovered, nothing seems impossible.
To prove their hypothesis, scientists at the London School of Medicine and the School of Economics interviewed several thousand people. As a result, volunteers who had two copies of the gene for happiness from both parents turned out to be optimists and not prone to any depression. The study was published by Jan-Emmanuel de Neve in the Journal of Human Genetics. At the same time, the scientist emphasized that other "happy genes" could soon be found.
Nevertheless, if you, for some reason, have a bad mood for a long time, you should not rely too much on your body and blame Mother Nature for “cheating you with happiness”. Scientists say that human happiness depends on many factors: "If you are unlucky, you lost your job or separated from loved ones, then this will be a much stronger source of unhappiness, no matter how many genes you have," said de Neve …
Genes and diseases
Genes also influence which diseases a person may be prone to. In total, about 3500 genetic diseases have been described to date, and for half of them a specific culprit gene has been identified, its structure, types of disorders and mutations are known.
Longevity
The longevity gene was discovered by scientists at Harvard Medical School in Massachusetts back in 2001. The longevity gene is actually a sequence of 10 genes that can hold the secret to long life.
During the implementation of the project, the genes of 137 100-year-old people, their brothers and sisters, aged 91 to 109, were studied. All subjects found "chromosome 4", and scientists believe that it contains up to 10 genes that affect health and life expectancy.
These genes, as scientists believe, allow their carriers to successfully fight cancer, heart disease and dementia, and some other diseases.
Shape type
Genes are also responsible for body type. So, the tendency to obesity often occurs in people with a defect in the FTO gene. This gene disrupts the balance of the "hunger hormone" ghrelin, which leads to impaired appetite and an innate desire to eat more than necessary. Understanding this process gives hope for the creation of a drug that reduces the concentration of ghrelin in the body.
Eye color
Traditionally, it is believed that eye color is determined by heredity. A mutation in the OCA2 gene is responsible for light eyes. The EYCL1 gene of chromosome 19 is responsible for blue or green color; for brown - EYCL2; for brown or blue - EYCL3 chromosome 15. In addition, the genes OCA2, SLC24A4, TYR are associated with eye color.
Even at the end of the 19th century, there was a hypothesis that human ancestors had extremely dark eyes. Hans Eiberg, a modern Danish scientist at the University of Copenhagen, has done scientific research to support and develop this idea. According to the results of research, the OCA2 gene, which is responsible for light shades of the eyes, whose mutations disable the standard color, appeared only during the Mesolithic period (10,000-6,000 BC). Hans has been collecting evidence since 1996 and concluded that OCA2 regulates the production of melanin in the body, and any changes in the gene reduce this ability and disrupt its functioning, making the eyes blue.
The professor also claims that all blue-eyed inhabitants of the Earth have common ancestors, because this gene is inherited. However, different forms of the same gene, alleles, are always in a state of competition, and the darker color always "wins", as a result of which parents with blue and brown eyes will have brown-eyed children, and only a blue-eyed couple can have a baby with eyes of cold shades.
Blood type
The blood group of a future baby is the most predictable of all hereditary traits. It's pretty simple. Knowing the blood group of the parents, we can say what it will be in the child. So, if both partners have 1 blood group, then their baby will have the same. With the interaction of 1 and 2, 2 and 2 blood groups, children can inherit one of these two options. Absolutely any blood group is possible in a child whose parents are of groups 2 and 3.