Question

c)

d) Design an experiment to determine if this mutant allele identified disrupts the function of the encoded White protein. You have heterozygous female flies X⁺X^wnm (where “nm” stands for the new white gene mutation you have identified), wildtype X⁺Y male flies, and white eye X^wY male flies.

Could you cross your heterozygous female flies with wildtype, white eye, or either of these male fly options to address this question? Briefly explain your answer. (Hint: use scratch paper to draw out the Punnett squares for each of these two options) (2pt)

e) Following up on this, which male fly genotype will you select to perform your cross? X⁺Y or X^wY and why?

Answer 1

Answer (d): Here we want to find out that which one of the two given male flies should be crossed to given heterozygous female fly to disrupt the function of encoded white protein.

Let we cosider both the cases one by one-

Case 1: when heterozygous female fly is crossed with wild-type male fly-

Genotype of Wild type male fly = X+Y.

Genotype of given female fly = X+Xwnm.

Showing the cross results using punnet square-

Case 2: when heterozygous female fly is crossed with white eyed male fly-

Genotype of White eyed male fly = XwY.

Genotype of given female fly = X+Xwnm.

Showing the cross results using punnet square-

Hence, when we will cross the heterozygous female with the given males, we will get the results as shown above.

Answer (e): We can see here that in case 2, white eye charater is not disrupted, it appears in first possibility. However, in case 1, there is possibility of appearing of white eye character. Hence we will choose case 1, if we want to disrupt white eye character.