The existence of four blood groups was proved by scientists in the early twentieth century.
Studies have shown that the child's blood type will depend on the blood group of the parents, that is, it is inherited genetically.
What blood groups exist
As a result of research by Austrian scientistsKarl Landsteiner and his students A. Shturly and A.Fon Dekastello created a blood classification system called "AV0", which is still in use. According to this system, there are four blood groups:
I (0) - it is characterized by the absence in the blood of special substances - antigens A and B-
II (A) - it contains antigens A-
III (AB) - is characterized by the presence of B-
IV (AB) - in the blood there are antigens A and B.
This discovery helped to eliminate losses in blood transfusions, because due to various characteristics, donor blood could harm the patient's body.
What type of blood will the child have?
In further studies, scientists have been shown,That the principles of obtaining a blood group in a child and other genetic traits will be identical. According to the laws of Mendel, formulated in the second half of the nineteenth century, parents with the first blood group produce children without antigens A and B (that is, having the first blood group). At the parents having the second group of blood, there are children with the first or with the second group of blood. In spouses with a third blood group, children with the first or third blood group are born.
Parents who have a first or second, orThe first and third blood groups, children are born with one of these groups. If one of the spouses has a fourth group, the child can not have the first blood group. If one of the spouses has the first group, they can not have a child with a fourth blood group. The spouses with the second and third group have children with any blood type.
Principles of inheritance of the Rh factor of blood
The Rh factor is called the antigen (protein),Which is located on the surface of red blood cells. It is present in the blood in about 85% of people, that is, they are Rh-positive. In the absence of this antigen, they speak of Rh-negative blood. These factors are denoted by the letters Rh: negative with a minus sign, positive with a plus sign.
If both parents have a negative Rh factor, they can only have a child with Rh-negative blood.
Positive Rh factor is dominantSign, and negative - recessive. If both parents in the genotype have both signs, they will have a positive rhesus. However, in this case, there is a probability (25%) that the child in this case is rhesus negative. That is, if both parents or one of them has a positive Rh factor, they can have a child with both Rh-positive and Rh-negative blood.