kaplan25 - nishi

[ArchivalUser]

A woman who is blood type A accuses a man of fathering her child. The accused man is found to be blood type O and the child is blood type B. What is the most reasonable interpretation of these results?
A. The accused man cannot be the father
B. The accused man is the father
C. The woman cannot be the mother
D. The woman is the mother
E. The results are inconclusive

[ArchivalUser]

a.

[ArchivalUser]

C???

[ArchivalUser]

correct answer is A. Type O is the recessive phenotype at the ABO locus. Therefore, the man™s genotype was OO and he could pass on only an O allele. The child was type B, so since the A and B alleles are codominant to each other and dominant to the O allele, the true father of the child must have donated the B allele to the child. The mother must have been blood type AO, and she donated her O allele to the child.