Genetics <span title="problem...........................................................................................?">problem.....................</span>

Question

1. in drosophila, gray body color is dominant to ebony body color, while long wings are dominant to vestigial wings. work through the following crosses through F2 generation and determine the genotypic and phenotypic ratios for each generation. Assume the parents are all homozygous

a. gray, vestigial x ebony, long

b. gray, long x gray, vestigial

7. In guinea pigs, rough coat as dominant over smooth; black coat is dominant over white. Arough black guinea pig bred with a rough white one gives the following results:

rough black - 28

rough white 31

smooth black 11

smooth white 10

a. what are the genotypes of the parents?

b. to comfirm your answers to the previous question, show a diagram of this cross, indicating all the genotypes and phenotypes involved.

show your solution

Answer 1

1.a. P: GGll x ggLL = all offspring are GgLl

F1: GgLl x GgLl = 9:3:3:1 phenotypic ratio in the F2

1.b. P: GGLL x GGll = all offspring are GGLl

F1: GGLl x GGLl = 3:1 phenotypic ratio in the F2

7.a.  Since the phenotypic ratio is close to 3:3:1:1, the parents were: RrBb x Rrbb

7.b. You have to do this yourself, but the gametes that the parents can make are:

RrBb parent can make RB, Rb, rB, and rb

Rrbb parent can make Rb and rb