Question

a man with type a blood and a woman with type b blood have a child with type o blood.
part a
what is the genotype of the man?
○ ii
○ $i^a i^a$
○ $i^b i$
○ $i^a i^a$

Explanation:

Step1: Recall Blood Type Genetics

Blood type A can have genotypes $I^A I^A$ or $I^A i$. For a child with type O blood (genotype $ii$), both parents must contribute an $i$ allele. The man has type A blood, so to pass an $i$ allele, his genotype must include $i$.

Step2: Evaluate Options

• $ii$: This is type O, not A. Eliminate.
• $I^B i$: This is type B (since $I^B$ is dominant), not A. Eliminate.
• $I^A I^A$: This genotype can only pass $I^A$ alleles, so the child couldn't get $i$ for O blood. Eliminate.
• $I^A i$: This is type A ( $I^A$ dominant over $i$) and can pass $i$ allele, which is needed for the child's $ii$ genotype (along with the woman's $i$ from her type B genotype, likely $I^B i$).

Answer:

$I^A i$ (the option labeled $I^A i$)