Epistasis is observed when the allele of one gene masks the effects of another gene. Use the Punnett square to answer the question.

Question

What color would a dog's fur be if its genes are aabb?

Responses

black
black - no response given

yellow
yellow - no response given

white
white - no response given

brown

Answer 1

To determine the fur color of a dog with the genotype aabb, we need to consider how the alleles interact based on the principles of epistasis.

In many dog coat color genetics, certain alleles may mask the expression of others. A common example involves two genes:

1. Gene A (with alleles A and a): The presence of at least one dominant allele A typically results in a non-yellow pigmentation.
2. Gene B (with alleles B and b): The presence of at least one dominant allele B generally leads to a black fur color, while bb can result in a different color (often brown or yellow, depending on the genetics).

However, if we look at the aabb genotype:

• The "aa" part suggests that this dog does not express the typical black/brown pigmentation.
• The "bb" part generally results in yellow fur if the dog has the genotype that does not mask it.

Thus, with the genotype aabb, the dog would typically have yellow fur based on the common interpretations in dog color genetics.

So, the answer is yellow.