Inheritance of blood group
During the formation of sex cells during meiosis is transmitted over a single link of information, and when you merge parent cells in the ovum information connected to a single DNA, where each gene consists of a pair of signs. There are dominant traits, i.e. overwhelming and recessive – weak, which can occur only in the absence of dominants.
The AB0 gene, which is responsible for group membership, is located in chromosome 9 34 along the segment. In the gene may be dominant A and B or the recessive trait is 0, i.e. the lack of information on encoding glycoprotein A or B.
Parents with blood group gene is a recessive trait, i.e. 0 and such parents to their children always convey only 0. Father or mother with the second group can have one of two sets of genetic information – AA or A0, it turns out that the child will get A or 0. The third group is caused by the set of BB or B0, to the child of such parents will give B, or 0. But the parents of the fourth group of blood in your genetic code are in the set AB, and their generation can be transferred to any dominant - A or B.
Depending on which characteristics will merge into a gene in the child, manifested blood. If both parents will give the baby 0 it will be with the first group of blood, and the parents can have I, II or III group, i.e., any where one of the signs 0. In cases when both parents transmit A symptom or one of the parents passes A and the other 0 – the child receives a second blood group. Thus, it appears that group II the child can be inherited from parents with the second group, or from my mom with the I group and from the Pope with II or IV. The third group of blood is formed in the transmission from parents dominant trait B, the gene set can be BB or B0, i.e. the father or the mother can have the first group, then the other parent is III or IV, or both parents have the II, IV group. To inherit the fourth group kid can when he one of the parents will give A and the other B, ie should merge both dominant. This genetic code is obtained by fusion of gametes of parents with IV group, or when connecting dominants from groups II and III.
Inheritance of the RH factor
RH factor is determined by dominant-recessive trait, despite the fact that RH positive is dominant and negative is recessive trait. Depending on which genetic set inherited by the child, will manifest its phenotype. So, if the gene has at least one plus (positive sign of RH), the baby will have RH-positive factor. But the negative may only become apparent when you inherit two drawbacks, i.e. the absolute recessive trait.
Sometimes both parents have the dominant RH positive and the baby is born with RH-negative blood. This fact suggests that both parents are heterozygous and each of them gave the baby a recessive trait that could occur in parents, because they have a second dominant positive RH.
Often it happens that a child is born with identical blood group and RH factor of the parents. But this does not mean that he inherited the father's or the mother's blood. In this case, each of the parents gave the fruit half information, but it merged so that phenotypically like either parent. For instance, Mama III (BB) dad and I (00) gave the kid a set B0, and he will also appear third blood group as my mom, but the genetic code will be different.
Advice 2 : If passed, the RH factor is inherited?
RH factor is one of the most important characteristics of blood along with the group. Positive RH factor indicates the presence on erythrocytes of a special protein. This feature may be inherited. The positive RH of the fetus during pregnancy in RH negative woman can become a cause of rhesus-conflict.
What is RH factor?
Human blood consists of red cells – erythrocytes. In some cases, their surface contains antigens of group D, in such situations, talking about the positive RH. These substances are present in the blood approximately 85% of people, the remaining 15% negative RH factor, that is, they have these antigens are absent. In the blood there are other antigens, but their presence is not of such great importance in blood transfusion or pregnancy.
Transfusion of RH-positive blood to a person with a negative RH factor leads to the destruction of red blood cells, which causes the so-called pathological hemolysis – this is immune response to unfamiliar substances. People with a negative rhesus factor need to be taken when blood transfusion. You should also pay attention to their RH factor in pregnancy: RH negative mother and a positive father can cause rhesus incompatibility and lead to the development of hemolytic jaundice in the child, stillbirth or infant death.
RH positive people can receive blood from any RH factors, and pregnant women with this blood should not be afraid of conflict, even if the father is RH negative.
How is rhesus factor inherited?
The genes for RH factor are inherited according to the same principles as any other genes. So, when you inherit the dominant RH positive: in most cases, the "meetings" of the two genes responsible for different RH factors, wins the one who is responsible for positive. But not in all cases: even with a positive RH factor from both parents, a child may be born with a negative, but the probability of this is less. This happens because the alleles of the parents can attend different genes: one is dominant, causing a positive RH, and the other just exists but does not manifest itself. Since the formation of gametes alleles are divided into two parts, at the time of conception can meet the egg and sperm with the genes responsible for negative RH factor. In this case, and the child inherits the RH.
Clearly we can only assert that parents with negative RH-factor is going to be the same child as their genotype no gene responsible for the presence of antigens on erythrocytes. If one parent is RH negative and the second positive, then the child is equally likely to inherit one and the other.