Blood is divided into groups based on the presence of certain antigens and antibodies to them. There are four main groups: 0 (I), A (II), B (III), as well as AB (IV). Each of them corresponds to a number, and the letter indicates the absence or presence of specific antigens. This is also a measure of compatibility.
In humans, genetic
blood counts do not change throughout life. This is a specific identifier that children inherit from their parents. Groups are more ancient than nationalities and races. The main difference between different people, according to many scientists, is not in ethnic origin and skin color, but in the
composition of the blood.The most common blood type is the first. For transfusion, it is most suitable because it does not contain antigens. The second one is suitable only for people of the same and fourth group because of the presence of antigens A. The third one is suitable only for owners of the third and fourth, and the last one can be transfused only to people with the same blood group.
However, not only the presence or absence of antigens, but also the Rh factor is important. It is determined by the presence of protein on the surface of red blood cells. If it is, then the rhesus is positive, and if it is absent, it is negative. About 85% of the world's population have a positive Rh factor. For example, a third negative blood group is much less common than a positive one. The same goes for the rest.
The first, most common blood type is found in 45% of the world population. Next in order are the rest. The rarest group is the fourth. If we take into account the Rh factor, then the most common blood type is the first positive, and the rarest - the fourth negative.
The group and Rhesus must be considered during pregnancy planning. If the fetus inherits the father’s indicators, which are incompatible with the mother’s blood, then problems are possible during pregnancy. However, modern medicine is quite capable of preventing them.
The composition of the blood has been formed for many thousands of years and is associated with the formation of the immune and digestive systems. Blood type 1 positive in antiquity was the whole of humanity. The digestive tract was then most suited for the digestion of meat protein foods.
Therefore, people in this category still have high acidity of gastric juice, and they are prone to peptic ulcer. The first is still the most common blood type. With the increase in the number of mankind, meat has become less accessible due to its shortage, so people began to eat plants more and more. This influenced the qualitative composition of the blood, which led to the emergence of other groups that endowed people with many useful qualities.
For example, owners of blood with gene A are more adapted to life in the modern world. This gene at one time became a guarantee of the survival of people during the terrible epidemics of plague and cholera. People with this blood composition are less aggressive and have more contact, which helps them feel good in society.