Interesting facts from the world of medicine sometimes present us with amazing surprises. For example, do you know what chromosomes are and how they affect humans?
We propose to sort out this issue in order to dot the i's once and for all.
Looking at family photos, you might have noticed that members of the same kinship are similar to each other: children - like parents, parents - like grandparents. This similarity is passed down from generation to generation through amazing mechanisms of genetic inheritance.
All living organisms, from unicellular algae to African elephants, have chromosomes in the nucleus of the cell - thin long filaments that can only be seen under an electron microscope.
Chromosomes (ancient Greek χρῶμα - color and σῶμα - body) are nucleoprotein structures in the cell nucleus, in which most of the hereditary information (genes) is concentrated. They are designed to store this information, its implementation and transmission.
How many chromosomes does a person have
At the end of the 19th century, scientists found out that the number of chromosomes in different species is not the same.
For example, a pea has 14 chromosomes, a rat has 42, and a person has 46 (that is, 23 pairs). Hence, the temptation arises to conclude that the more of them, the more complex the creature possessing them. However, in reality, this is completely not the case.
Of the 23 pairs of human chromosomes, 22 are autosomes and one pair are gonosomes (sex chromosomes). Sexual differences have morphological and structural (gene composition) differences.
In the female body, a pair of gonosomes contains two X-chromosomes (XX-pair), and in a male, one X- and one Y-chromosome (XY-pair).
The sex of the unborn child depends on the composition of the chromosomes of the twenty-third pair (XX or XY). This is determined by fertilization and fusion of the female and male reproductive cells.
This fact may seem strange, but in terms of the number of chromosomes, humans are inferior to many animals. For example, some unfortunate goat has 60 chromosomes, and a snail has 80.
Chromosomes are made up of a protein and a DNA (deoxyribonucleic acid) molecule that looks like a double helix. Each cell contains about 2 meters of DNA, and all in the cells of our body there are about 100 billion km of DNA.
An interesting fact is that in the presence of an extra chromosome or in the absence of at least one of the 46, a mutation and serious deviations in development (Down's disease, etc.) are observed in a person.
It was in connection with this scientific fact that the "intelligent" insult spread among the people: "What, you have an extra chromosome?"
Now you know general information about the principles of heredity. In general, this topic is very interesting, albeit extremely complex.