The figure shown indicates two Labrador retrievers that are both homozygous recessive for fur color.Why is one dog brown and the other is yellow?

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The difference in fur color is due to epistasis, a genetic phenomenon where one gene masks or alters the expression of another gene. The gene responsible for fur color in Labrador retrievers is epistatic, meaning it controls the expression of another gene that determines whether the pigment for brown fur or yellow fur will be produced. In this case, both dogs are homozygous recessive for fur color, so they both lack the gene that produces brown fur. However, the brown dog has a dominant allele for the gene responsible for the production of the pigment that creates yellow fur, while the yellow dog has a recessive allele for that same gene, resulting in a lack of pigment production and yellow fur.

The Figure Shown Indicates Two Labrador Retrievers That Are Both