The ABO blood groups in humans are determined by a multiple allelic system in which I^A and I^B are codominant and are dominant to i^O. If an infant born to a type O mother also is type O, possible genotypes for the father are A) O or A. B) A or B. C) O only. D) O, A, or B. E) impossible to determine.

Question

Quizplus · Accepted Answer

The infant has type O blood, which means they must have inherited an i^O allele from both parents. The mother, being type O, can only contribute an i^O allele. The father must also contribute an i^O allele, meaning he could be type O (i^Oi^O), type A (I^Ai^O), or type B (I^Bi^O).

The ABO Blood Groups in Humans Are Determined by a Multiple