Question

Two people have the genotype IAIB. Of the following options, what possible genotypes could their children have?

Choose all that apply:

(A) IAi

(B) IAIB

(C) IBIB

(D) IAIA

Answer 1

Children of parents both with the genotype IAIB can have the genotypes IAIB or IAIA. Option (A) IAi is not possible because neither parent has the i allele. Option (C) IBIB could occur but is not listed among the options given.

Step-by-step explanation:

When two people with the genotype IAIB have children, their children could potentially have one of the following genotypes:

• IAi
• IAIB
• IBi
• IAIA

Each parent with genotype IAIB can produce gametes that carry either the IA allele or the IB allele, since these are the alleles in each parent's genotype. There are no i alleles to pass on, so the gametes will not carry the i allele (which encodes the O blood type). When these gametes combine, we can see the following possible genotypes for their children:

• (A) IAi: This is not possible since neither parent possesses the i allele.
• (B) IAIB: This is possible since both parents carry IA and IB alleles.
• (C) IBIB: This is not listed as an option but is indeed possible with two IB alleles combining.
• (D) IAIA: This is also possible if both IA alleles combine.

Therefore, of the options provided, (B) IAIB and (D) IAIA are the possible genotypes for their children.