If a boy has blood type O and his mother has blood type A,what is the genotype of his father?
Answer Details
If the boy has blood type O, that means he received an O allele from his father, as O is recessive and masks the expression of A and B alleles. Since his mother has blood type A, she could have either genotype AA or AO, with either of them possessing an A allele. Therefore, the father must have genotype AO or OO to pass on an O allele to the son. So, the possible genotypes of the father are AO or OO.