Even at the beginning of the last century, scientists proved the existence of different blood types. This is a whole system of a set of genes received from parents. Based on the results of numerous studies, mom and dad pass on the blood type to the child. What can it be, how is it inherited? In this article we will try to answer these questions.
A bit of history
Scientist Karl Landsteiner in the course of experiments revealed that during the mixing of the blood of some people with blood taken from others, gluing of red bodies (erythrocytes) can occur, which causes clots to form. After that, the scientist began a detailed study of red blood cells, as a result of which he found substances of a special type. He divided them into A and B categories. Karl also discovered a third category, describing cells that do not contain special elements.
After some time, A. von Decastello and A. Sturli found erythrocytes that contained A and B elements at once.
As a result of the work of these scientists, the ABO system was created,which divides blood into groups. This system is familiar to us in the following form:
- I(O). This is the first group, which is characterized by the absence of antigens A and B.
- II(A). Blood with antigen A.
- III(B). Blood with antigen B.
- IV(AB). This group is characterized by the presence of two types of antigens at once - both A and B.
Following this discovery, doctors were able to eliminate transfusion losses that once occurred due to the incompatibility of donor blood and the recipient. Although there have been cases of successful transfusion.
The ABO system made it possible to completely change the opinion about the nature of blood. Later, geneticists proved the identity of the principles of inheritance of a blood type by a child from parents, as well as obtaining other signs. In the second half of the twentieth century, Mendel discovered the laws of heredity, based on the results of experiments on peas.
Mendel's laws
Scientists have proven laws that determine which blood type a child will inherit from parents:
- A father and mother with the first group can only have children with the first group. This is due to the fact that they do not have A and B antigens.
- If parents have the first and second groups, then the kids will have the same groups. The same will happen if the parents have the first and third.
- For parents with the fourth blood group, the child will have any blood except the first group.
- There are people who have A and B antigens, but they don't show up. This variety is most commonly found inHindus and was called the "Bombay phenomenon".
Rh factor
If in a family both parents have a positive Rh, and the baby is negative, then distrust of the spouse may arise, although it is formed from scratch.
The Rh factor is a unique, special protein that is located on the surface of red blood cells. Approximately 85 percent of the world's population has this protein, and the rest do not. In the first case, a positive (+) Rh factor is diagnosed, and in the second, a negative (-). These same factors are referred to as Rh. To conduct research, they usually take a couple of genes.
Like the blood type, the child inherits the Rh factor, but a slightly different principle applies here.
Rh positive is usually denoted by the Latin DD or Dd. Most often, it is dominant, and negative Rh is denoted by dd and it is recessive. If the spouses have a heterozygous Dd Rh, then 75% of the children will have a positive (+) Rh, and the rest will have a negative (-).
If the parents are carriers of Dd and Dd, then they can have children with different genotypes: DD, Dd, dd.
It is easier to understand the principle of inheritance using the table:
ABO blood inheritance
And what type of blood will the child have if the parents have the first and second group? These questions are often asked by future parents. The answer to it and other questions in the table:
Heredity
Besidesblood groups, the child from the parents shows other signs. For centuries, people have fantasized about what a child could be, but heredity takes its toll.
Today, ultrasound allows you to accurately determine the sex of the unborn baby, to see developmental anomalies. Genetics allows you to determine what will be the color of hair, eyes, whether the child will have an ear for music. These traits are dominant and recessive. To find out what is the probability of inheritance, you should refer to the laws of Mendel.
Dominant properties include brown eyes, curly hair, the ability to roll the tongue into a tube. If one of the parents has these signs, then the child is likely to get them.
It will be less joyful that if parents turn gray early, go bald, then this will also be passed on to children, since this is also a dominant trait. Also, kids will most likely have a large gap between the front teeth, myopia.
But blue eyes, straight hair, fair skin are all recessive traits that are harder to inherit.
Gender determination during pregnancy
For a long time, women have been accused of not having heirs in their families. But are women to blame? Genetic scientists have found that eggs and sperm have 23 chromosomes, of which 22 match the sex cells of the spouse, and the latter does not match - this is a female pair - XX, male - XY.
The sex of the future baby depends on the set of dad's chromosomes, that is, on those 23 chromosomes thatfound in spermatozoa.
ABO Compatibility
At the stage of pregnancy planning, when partners are suspected of immunological infertility, they check the compatibility of blood types to conceive a child.
Incompatibility occurs only when agglutinogens are found in the blood of one of the spouses, and the agglutinins corresponding to them, for example, A and a, B and b, are found in the other. In such cases, fetal erythrocytes stick together.
In rare cases, children may begin to form a third blood group that is incompatible with the maternal ABO. In such cases, an immunological conflict occurs, i.e. an early miscarriage occurs or the baby is born with hemolytic disease.
Rh compatible
The blood type of father, mother, child can rarely be incompatible, most often there is an Rhesus conflict. This phenomenon occurs when a woman is Rh negative and becomes pregnant with an Rh(+) positive child.
In this situation, the fetal proteins enter the mother through the general bloodstream, where they are met by the immune system. She perceives these proteins as foreign objects. At this point, the female body begins to produce antibodies that cause the death of red blood cells in the fetus.
If this is the first pregnancy for a woman, then there are no serious changes, since the immune system reacts slowly to a fetus with a positive Rh factor. And does not have time to develop the required amount of antibodies. When repeatedPregnancy with an Rh positive child, the immune system begins to kill red blood cells, but if the fetus is Rh negative, the baby will develop normally, without threats.
Incompatibility of partners
Before you decide to have a baby, you should be prepared. It includes not only the cure of all current diseases, but also a compatibility test. In some cases, you have to turn to genetics. Usually such a need arises in cases where the mother and the child have blood types that conflict.
Usually, in case of ABO incompatibility, spouses have to look for alternative options for conceiving or adopt a child.
If partners are incompatible with the Rh factor, you should not worry during the first pregnancy, as the female body will not “attack” the fetus. After giving birth, the first child must determine the blood type and Rh factor. If the first pregnancy ends in an abortion, miscarriage, then the woman is injected with anti-Rhesus immunoglobulin to prevent the Rhesus conflict between mother and fetus.
Knowing whether the blood type of the child and the mother can be incompatible, which parent groups and Rh factors are suitable for each other, you can safely plan a pregnancy. In the event that there is a possibility of incompatibility, then this can be tried to be corrected by applying the method recommended by the doctor.
