A man of blood group B is being sued by a woman of blood group A for paternity. The womans child is blood group O. a) If this man is actually the father of this child, specify the genotypes of both parents? b) If it was impossible for this group B man to be the father of a type O child, specify his genotype? c) If a man was blood group AB, could he be the father of group O child?
Answer:
a) In order for the man with blood group B to be the father of a child with blood group O, the genotypes of both parents need to be considered. Blood group A is characterized by the presence of the A antigen on red blood cells, while blood group B is characterized by the presence of the B antigen. Blood group O, on the other hand, is characterized by the absence of both antigens.
The possible genotypes for individuals with blood group A are AA or AO, while the possible genotypes for individuals with blood group B are BB or BO. In this case, since the child has blood group O, we know that the child’s genotype must be OO.
If the man is the biological father of the child, he must have contributed an ‘O’ allele to the child. Therefore, his genotype must be BO, since individuals with blood group B can have either two B alleles (BB) or one B allele and one O allele (BO). The woman’s genotype could be either AA or AO.
b) If it is impossible for the group B man to be the father of the type O child, it means that he cannot contribute an ‘O’ allele to the child. This would suggest that his genotype must be BB, which means he has two B alleles. With this genotype, it is not possible for him to have a child with blood group O.
c) A man with blood group AB can only pass either an ‘A’ or a ‘B’ allele to his biological child. Since individuals with blood group AB have both A and B antigens, they do not have an ‘O’ allele. Therefore, if a man with blood group AB is the biological father of a child with blood group O, it would mean that the child inherited an ‘O’ allele from the mother.
In this case, the genotypes of the biological parents would be as follows:
– The man with blood group AB would have the genotype AB (since individuals with blood group AB have one A allele and one B allele).
– The woman’s genotype could be either AO or BO, since she could pass either an ‘A’ or a ‘B’ allele to the child.
To summarize, in order for a man with blood group B to be the father of a child with blood group O, his genotype would be BO and the woman’s genotype would be either AA or AO. If it is impossible for the man to be the father of a type O child, his genotype would be BB. A man with blood group AB could not be the biological father of a child with blood group O, as individuals with blood group AB do not have an ‘O’ allele.