Mauble cats have long whiskers resulting from the Wh allele

Mauble cats have long whiskers resulting from the Wh allele which is dominant to the normal whisker allele wh. In these cats, gray fur color (G) is dominant to black fur color (g). A gray cat with normal whiskers mates with a black cat with long whiskers. (Explain / Show Work)

a) List the genotype(s) and phenotype(s) of the F1 offspring.

b) List the genotype(s) and phenotype(s) of the F2 offspring along with the expected ratios for each type.

c) If one of the F1 cats mated with a black cat with normal whiskers, what genotypes, phenotypes and ratios would you expect to see in the offspring?

Solution

Assume that the gene coding for long whiskers is, W and normal whiskers is w; W is dominant over w. Similarly, the gene coding for gray fur is G and back fur is g; G is dominant over g.

Given that a gray cat with normal whiskers (GG ww) is mated with a black cat with long whiskers (gg WW).

a). Assuming the cats are pure breeds, the parental cross is,

GG ww* gg WW --à Gg Ww (100% gray, long whiskers) ---à F1

b). The expected ratios of F2 offspring are,

Gg Ww* Gg Ww -à G_W_ (9/16, gray, long whispers), G_ ww (3/16, gray, normal whispers), gg W_ (3/16, black, long whispers), gg ww (1/16, black, normal whispers)

c). F1 cat (Gg Ww) is mated with a black cat with normal whiskers (gg ww)

Gg Ww* gg ww --à Gg Ww (1/4, gray, long whiskers), Gg ww (1/4, gray, normal whiskers), gg Ww (1/4, black, long whiskers), gg ww (1/4, black, normal whiskers)