In barkers, the dominant allele D causes a solid coat color; the recessive allel

Question

In barkers, the dominant allele D causes a solid coat color; the recessive allele d results in white spots

on a colored background. The black coat color allele L is dominant to the brown allele l, but these genes

are expressed only in the genotype e/e. Individuals that are E/_ are yellow regardless of L alleles. The

three genes are unlinked. A solid yellow male mates with a solid brown female. Their offspring are

comprised of 3 solid black, 2 solid brown, 1 spotted yellow, and 1 spotted black barkers.

PLEASE ANSWER ALL QUESTIONS:

A) What are the genotypes of each of the parents?

B) Describe the relationship between genes E and L.

C) What is the probability that the next pup will be spotted brown?

Explanation / Answer

Part a-
From the phentoypes of the offsrpings, we can deduce the genotypes of the parents. For example, one of the offspring is spotted, which is a recessive trait, so we can say both the parents are Dd for coat color.
Also, we have brown female parent, so its "ee" and male is Ee. This is because offspring is black, indicating that this offspring has "ee', which is only possible, if both parents have one recessive allele.
After all such observations, we can conclude that the genotypes of parents are-

Male = Dd Ee Ll
Female = Dd ee ll

Part b-
The type of relation ehre is "Epistasis". This is because dominant E is suppressing the phenotype of L/l allele.

Part c-
Genotype of spotted pup = dd ll ee.

Probability = [1/4] * [1/2] * [1/2] = 1/16 or 6.25%

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