Question

in humans, three alleles affect blood type. the a and b alleles are codominant, and the o allele is recessive. an ab blood type father has children with an a blood type mother (genotype ao). what are the chances that their children will have ab type blood? choose 1 answer: a 25% b 50% c 75% d 100%

Explanation:

Step1: Determine parental alleles

Father (AB) has alleles \( A \) and \( B \). Mother (AO) has alleles \( A \) and \( O \).

Step2: Create Punnett square

	A	O
B	AB	BO

Step3: Count AB genotypes

From the square, AB appears 1 out of 4 times? Wait, no—wait, the Punnett square has 4 cells: AA, AO, AB, BO. So AB is 1? Wait, no, let's re - check. Father's gametes: A and B. Mother's gametes: A and O. So combinations: A (father) & A (mother) = AA; A (father) & O (mother)=AO; B (father) & A (mother)=AB; B (father) & O (mother)=BO. So AB is 1 out of 4? Wait, no, 1/4 is 25%? Wait, no, wait the Punnett square has 4 possible offspring genotypes. The AB genotype occurs once. Wait, but wait, the number of AB genotypes: 1. Total genotypes: 4. So probability is \( \frac{1}{4}=25\% \)? Wait, no, wait: Father: AB (gametes A and B), Mother: AO (gametes A and O). So the cross is (A,B) x (A,O). The possible offspring: AA (A from father, A from mother), AO (A from father, O from mother), AB (B from father, A from mother), BO (B from father, O from mother). So AB is 1 out of 4, which is 25%. Wait, but let's count again. The four combinations: AA, AO, AB, BO. So AB is 1. So the chance is 25%.

Answer:

A. 25%