The blood groups in humans, are known to have three alleles, and thus, distinguishes them from classic two-allele problems of pea plants. These alleles are IA, IB, and i. Both IA and IB show codominance to i. Thus, IAIA will have the same phenotype as IAi (Type A), and IBIB will have the same phenotype as IBi (Type B). A heterozygous IAIB will give the additional phenotype, type AB, and the homozygous recessive, ii, will give a type O.
It was suspected that two babies had been switched in a hospital. Mr. and Mrs. Brown received baby #1 and Mr. and Mrs. Green received baby #2. Blood typing tests on the parents and the babies gave the information shown below:
Did both families get the right baby? Why?