Which example illustrates epistasis in dogs?

Which example illustrates epistasis in dogs?

• A. White fur in Alaskan Huskies
• B. Coat color in Labrador Retrievers where yellow masks black or chocolate
• C. Shedding patterns in golden retrievers
• D. Colorblindness in certain breeds

Answer: (B)

Epistasis refers to a genetic interaction where the expression of one gene interferes with or masks the expression of another gene at a different locus. In the case of Labrador Retrievers, coat color is determined by two different genes: one gene determines whether the coat is black or chocolate, while a second gene influences the presence of the yellow coloration. In this scenario, if the second gene is present in a certain form, it can mask the expression of the first gene. As a result, a Labrador that carries both genes for black or chocolate may appear yellow if the second gene is the dominant one that promotes yellow fur. This relationship is a classic example of epistasis because one trait (the fur color) is masked by the influence of another trait (the yellow coloration), illustrating the complexities of genetic inheritance beyond simple Mendelian ratios. In contrast, fur color in Alaskan Huskies reflects a different genetic principle, shedding patterns in golden retrievers are likely influenced by environmental factors rather than direct genetic interactions, and colorblindness is a trait that follows a different inheritance pattern related to sex-linked genetics rather than epistasis.

Epistasis refers to a genetic interaction where the expression of one gene interferes with or masks the expression of another gene at a different locus. In the case of Labrador Retrievers, coat color is determined by two different genes: one gene determines whether the coat is black or chocolate, while a second gene influences the presence of the yellow coloration.

In this scenario, if the second gene is present in a certain form, it can mask the expression of the first gene. As a result, a Labrador that carries both genes for black or chocolate may appear yellow if the second gene is the dominant one that promotes yellow fur. This relationship is a classic example of epistasis because one trait (the fur color) is masked by the influence of another trait (the yellow coloration), illustrating the complexities of genetic inheritance beyond simple Mendelian ratios.

In contrast, fur color in Alaskan Huskies reflects a different genetic principle, shedding patterns in golden retrievers are likely influenced by environmental factors rather than direct genetic interactions, and colorblindness is a trait that follows a different inheritance pattern related to sex-linked genetics rather than epistasis.