The father is type B and the mother is type O, what type of blood is the child

There was a couple who both had blood type "A", so they thought that the child's blood type must be "A" type. But when I got the test sheet, my daughter's blood type was "O" type. What's going on? Let's take a look at the way blood type is inherited.

Blood type is determined by genes located on chromosomes. Human cells contain 23 pairs of chromosomes, half of which come from the father and the other half from the mother, and these chromosomes carry thousands of genes from both parents that are passed down from generation to generation.

ABO blood group is determined by three blood group genes, A, B, and O, and the blood group genes are located on the 9th pair of chromosomes. Since A and B are dominant genes and O are recessive genes, as long as one of the 9th pair of chromosomes has a gene A, regardless of whether the corresponding locus of the other chromosome is a and O genes, it will be characterized by blood type A. For type O blood, it must be the 9th pair, and both chromosomes have the same O gene.

If chromosome 9 has a gene A and a gene on the other chromosome, it is blood type AB. According to this reasoning, if the man of a couple has blood type A and the woman has blood type O, then their children's blood group inheritance may have two combinations, that is, 3 4 people have blood type A and the other half have blood type B. Therefore, the blood type of the child can be different from that of the mother or the father.

The inheritance of the three antigens of ABO is controlled by three alleles, and the blood group gene is the complex allele, and there are three blood group genes at the relative locus, namely A, B or O, so the sum of genes at the relative locus is AA, BB, OO, AB, AO or BO Six combinations are called genetic formulas. A or B is a dominant gene, O is a recessive gene, and the phenotypes corresponding to the above genetic formulas are A, B, O, AB, A, and B, which are actually four types: A, B, O, and AB.

When the sperm and egg cells are combined, the relative chromosomes of the paternal and maternal genus are paired in pairs, so that half of a trait of both parents is passed on to the child, such as the father's blood type A, the inheritance formula is AO or AA, assuming that it is AO, half of its germ cells carry type A genes, and the other half have type O genes. The mother is type B, and her inheritance formula is BO and BB, and if it is assumed to be BO, the child born can be type A, B, O, AB. Assuming that the mother is BB, the child will be phenotypic AB or B.

Tips: The type of human blood is called blood type. There are four types of ABO blood group system: A, B, O and AB.

They differ in the antigen they contain on their respective red blood cells. For example, a person with a A antigen on red blood cells is blood group A, a person with both A and B antigens is blood type AB, and a person with no A or B antigen is blood type O, but the serum of a person with blood type A naturally contains B antibodies, and the serum of people with type B contains antibodies to A, and the serum of people with type B generally has no antibodies, while people with type O have antibodies to A and B. Because the agglutination reaction will occur when the antigen and the corresponding antibody are mixed, and even the red blood cells will be destroyed and dissolved and hemolysis will occur, the blood type of the donor and the recipient must be strictly tested during blood transfusion, so as to transfuse the same type of blood, otherwise it will cause serious adverse consequences.

Blood type is genetically determined, there are three types of ABO blood group genes: A, B, I, A and B genes are dominant genes, I gene is recessive genes, and each person's blood type is determined by a pair of genes from the father and mother, respectively. To use your example, if the mother has blood type O, it means that her pair of genes that determine blood type can only be I-I; The father is blood type B, and his blood group genes are two possibilities, one is B-B (both homozygous type B) and the other is B-I (both heterozygous type B).

If the father is homozygous for type B, and he can only pass on the B gene to the child, then the child must have the B gene, which combines with the I gene that can only be provided by the mother of type O to form a B-I gene combination, which is explicit as blood type B (heterozygous). If the father is heterozygous type B, then what he passes on to the child may be either the B gene or the I gene; The B gene is paired with the mother's I gene to form B-I, and the penetrance blood group is B (heterozygous); If the I gene is paired with the mother's I gene, an I-I is formed, and the penetrant is type O.

Conclusion: The mother has type O blood and the father has type B, and most children may have type B and a few may have type O.

Hello: According to the law of human blood type heredity:

If the parents have blood type O+B, the children may have blood types O and B, and the blood types that cannot be have are blood types A and AB.

Therefore, it is possible to have two blood types, O and B, and either blood type.