Why could a man with type of blood not be the father O a baby with type AB blood?
The correct answer and explanation is:
Correct Answer:
A man with type O blood could not be the father of a baby with type AB blood because he does not carry the necessary A or B alleles to pass on.
Explanation:
Human blood type is determined by the ABO blood group system. The ABO blood group is controlled by a single gene that exists in three forms or alleles: A, B, and O. Each person inherits one allele from each parent, so the combinations can be AA, AB, AO, BB, BO, or OO.
Type O blood is represented by the genotype OO, meaning the individual inherited an O allele from both parents. The O allele is recessive, while A and B alleles are dominant. This means someone with type O blood does not have the A or B antigen on the surface of their red blood cells, and they cannot pass on an A or B allele to their child.
On the other hand, for a person to have type AB blood, they must have inherited one A allele from one parent and one B allele from the other parent. This results in both A and B antigens being present on the surface of red blood cells. Therefore, a child with type AB blood must have received one A allele from one parent and one B allele from the other parent.
Since a man with type O blood has only O alleles, he cannot provide an A or B allele. It is genetically impossible for him to father a child with AB blood, because he simply does not have the necessary alleles to contribute. This kind of genetic reasoning is often used in paternity testing to rule out potential biological fathers based on incompatible blood types.