5 A new beetle species includes individuals with the followi

5. A new beetle species includes individuals with the following elytra colors: red, blue, green, purple, orange, and green-and-orange.

Pure line crosses of red and blue produce all purple, and the F₁ produces 1 red: 2 purple: 1 blue.

Pure line crosses of green and red produce all green-and-orange, and the F₁ produces 3 green: 6 green-and-orange: 3 orange: 1 red: 1 blue: 2 purple.

a) Define epistasis. (2)

b) Fully explain the genetics of the elytra color in this species, and predict the offspring of a cross of the progeny from the two pure line crosses described above (so a purple beetle crossed with a green-and-orange beetle). (8)

Solution

a) Epistasis can be defined as gene interaction in which one gene does not allow expression of alleles at another locus.