A man with blood type A marries a woman with blood type B. One of their children has blood type O. Show how this is possible.

Answer 1

For this question we have to logically think out what parental genotypes can create this offspring then we will make a punnet square. Since we know the child is type O phenotype and we know that O is the recessive allele, the child must have OO phenotype meaning it must inherit an O allele from each parent. this means that the father is genotype AO and the mother is genotype BO. That means the cross for the punnet square would be BO x AO resulting in the 4 offspring possibilities: AB, BO, AO, and OO. (sorry I can't draw the punnet square in the text box)