Question

What are the genotype and phenotype ratios of potential offspring when a man with type AB blood marries a woman with type O blood? (Use a Punnett square)

Options:
A) Genotype: 1/4 IAIA, 1/4 IAi, 1/4 IBIA, 1/4 IBi; Phenotype: 1/4 Type A, 1/4 Type B, 1/2 Type AB
B) Genotype: 1/4 IAIA, 1/4 IAi, 1/4 IBIA, 1/4 IBi; Phenotype: 1/2 Type A, 1/2 Type B
C) Genotype: 1/4 IAIA, 1/4 IAi, 1/4 IBIA, 1/4 IBi; Phenotype: 1/4 Type A, 1/4 Type B, 1/4 Type AB, 1/4 Type O
D) Genotype: 1/4 IAIA, 1/4 IAi, 1/4 IBIA, 1/4 IBi; Phenotype: 1/4 Type A, 1/4 Type B, 1/4 Type AB

Answer 1

A man with type AB blood (IAIB) and a woman with type O blood (ii) can have offspring with two potential genotypes (IAi or IBi), leading to a phenotype ratio of 1/2 Type A and 1/2 Type B.

Step-by-step explanation:

When a man with type AB blood (genotype IAIB) marries a woman with type O blood (genotype ii), their offspring can have two potential genotypes: IAi or IBi. This is because the alleles IA and IB are codominant, and both are dominant over the i allele, which represents O blood. Using a Punnett square to determine the ratios, we can see that each child has a 50% chance of inheriting an A allele and a 50% chance of inheriting a B allele from the father, and the only allele they can inherit from the mother is an i.

The possible genotypes for their offspring are therefore 1/2 IAi (Type A blood) and 1/2 IBi (Type B blood). This also means the phenotype ratios are as follows: 1/2 Type A and 1/2 Type B. There is no possibility of their offspring having AB or O blood types because the mother is homozygous for O blood and cannot pass an A or B allele to the offspring.