Question

Merle is a marking pattern in canine coats that appears as a marbling of color in a solid coat. the merle gene displays incomplete dominance. cscs individuals display a solid coat cmcs individuals are merle and show patches of fur with a lighter, mottled effect cmcm individuals are "double merle" and show patches of fur with much more pronounced lightening another gene, fgf5, also influences coat phenotype and determines whether dogs display long or short coats, with short coats being dominant to long coats. Part a. determine the proportion of offspring phenotypes that would result when two merle dogs mate, if one dog is true-breeding for the long-coat trait and the other dog is true-breeding for the short-coat trait.

Answer 1

100% merle with long coats.

Step-by-step explanation:

All the offspring produced from the cross would be merle with long coats.

From the illustration:

Merle gene is represented by the genotype cmcs.

fgf5 gene determines the coat phenotype. Let the gene be represented by the allele A. A determines long coat traits and it is dominant over its alternate form, b, which determines short coat trait.

Now, two merle (cmcs) dogs were mated. One is true-breeding for long coat (AA) while the other is true breeding for short coat (aa).

cmcsAA x cmcsaa

Progeny genotype = cmcsAa

cmcsAa = merle with long coat.

Since A is dominant over a, all the progeny from the cross will be merle with long coat.