Question

In non-mendelian genetics, humans have 4 blood types in which A and B are codominant and o is recessive. I cross a person who is heterozygous for type A (AO) and a person who is heterozygous for type B (BO). How many people will end up with type o blood?

A. 0%
B. 25%
C. 50%
D. 100%

Answer 1

When crossing individuals with heterozygous A (AO) and B (BO) blood types, there is a 25% chance that an offspring will inherit two recessive alleles (OO), resulting in type O blood.

Step-by-step explanation:

In the scenario where a person who is heterozygous for type A blood (genotype AO) is crossed with a person who is heterozygous for type B blood (genotype BO), the potential genotypes of their offspring can be AI, BI, AB, or OO. Genotype OO would result in type O blood since 'i' is the recessive allele and there would be no dominant A or B allele to mask it. Using a Punnett square, we find that there is a 1 in 4 chance, or 25%, for an offspring to have genotype OO, thus type O blood. This makes option B the correct answer.