The human body develops in accordance with the instructions laid down in the genes, and therefore our appearance depends mainly on the hereditary information received from the parents. However, on the human body — even in the womb and especially in childhood — a deep influence and all kinds of environmental factors. This also leaves a mark on our appearance.
The closest relatives of our biological species are chimpanzees (common and dwarfish, or bonobos), followed by other anthropoid apes — gorillas, orangutans, gibbons. The difference between the hereditary information (genotypes) of all these creatures, "recorded" in the molecules of their DNA with the help of approximately 3.2 billion "letters", is no higher than 1.5%. This is 10 times less than between mice and rats, and 10 times more than between people who are close relatives.
Now, when the human and chimpanzee genomes are deciphered, there is a search for genes that determine our unique characteristics. However, in the process of evolution and changes in DNA can greatly change the work of whole groups of genes. Features of the regulation of the work of genes and their interaction with other hereditary information and the definition of the fundamental mind between people and monkeys. The structure of the genes themselves is not so important.
Articulate speech is almost the main feature that distinguishes us from anthropoid apes. Scientists have discovered one of the genes responsible for the development of speech - FOXP2. A person with a mutated FOXP2 gene can not talk.
Comparing the human FOXP2 genes and chimpanzees, the scientists found two small differences in the DNA composition. As a result, not completely identical proteins are formed, which regulate the work of other genes, which are even more closely related to speech. In other words, it would be wrong to speak of a single "gene of speech".
The maximum growth that a person can achieve is determined by his genes. However, its real height largely depends on the conditions of life before adulthood. Over the past 120 years, the average growth of Europeans has steadily increased due to the continuous improvement of conditions. In past times, such trends were observed periodically.
In the IX-XI centuries, when the climate in Europe was mild, the food abundant, and the population density was low, the average height of men was about 173 cm — as in our time. Then, because of the cold snap and the increase in the number of people, the bug was eaten and more often sick with infectious diseases. As a result, the average height of men declined until in the XVII-XVIII centuries it reached 163 cm.
On average in the developed western countries, this difference is close to 12 cm. At the dawn of the evolutionary life, a tall, strong man guaranteed a more abundant food and more reliable protection from enemies to a woman and her babies. In our time, growth is not associated with social status and rarely affects professional success, but high-ranking gentlemen continue to evoke greater interest among women due to ancient genetic memory. Accordingly, tall men are more likely to leave offspring by passing their genes to him. The very same men are drawn to the rapidly ripening "crumbs". Thus, the preferences in the choice of service partners by genes. Therefore, despite the emancipation and equal social opportunities of the sexes, their difference in average growth will not disappear soon.
If a person is overweight, his genes are to blame for this about 60%. Some of them affect the appetite, determining the intensity of the release of the hormones of hunger and satiety. The proportion of calories stored in the form of fat and burned for energy is also partly attributed to heredity.
However, in the overwhelming majority of cases, a congenital predisposition to obesity is not difficult to suppress by a healthy diet and high physical activity. Another matter is the rare genetic mutations that alter the activity of hormones and their receptors on the brain cells. This threatens with unquenchable hunger and a steady set of weight. There is no getting around without health care.
This is not all the interesting facts about the human body. But, I think that for now it is enough =) To be continued ...
