In the gel diagram shown here, A and B are both X-linked restriction polymorphisms with three alleles (denoted A₁, A₂, A₃ and B₁, B₂, B₃, respectively). Mo and Fa show the banding patterns corresponding to the genotypes of mother and father in a mating, and Da is the banding pattern corresponding to the genotype of a daughter. What is the daughter's genotype?

Question

Quizplus · Accepted Answer

From Mo's gel diagram, we can see that she has the A₁ and B₃ alleles. From Fa's gel diagram, we can see that he has the A₃ and B₂ alleles. For the daughter (Da), we look at the lanes where Mo and Fa overlap. In these lanes, we see bands corresponding to the A₃ and B₃ alleles (the band sizes match those of Mo and Fa in these lanes). Therefore, the daughter must have inherited one copy of A₃ from Mo and one copy of B₃ from Fa. Looking at the answers, the only option that fits this is B: A₁ B₃/A₃ B₂.

In the Gel Diagram Shown Here, a and B Are