Sometimes, the phenotypic expression of one gene affects/masks the expression of another independently assorting gene. This can be seen in the coat color of Labrador retrieves. This condition is known as epistasis. There are two types of epistasis: dominant epistasis and recessive epistasis.
The coat color of Labrador retrievers is determined by two genes that follow the law of independent assortment. If two black Labs that are heterozygous for both genes (BbEe) mate, what type of interaction will result in which modified phenotypic ratio?
A. Pleiotropy will result in a ratio of 9 black : 7 yellow Labs
B. Pleiotropy will result in a ratio of 9 black : 3 brown : 4 yellow Labs
C. Epistasis will result in a ratio of 9 black : 3 brown : 3 yellow : 1 purple Lab
D. Epistasis will result in a ratio of 9 black : 3 brown : 4 yellow Labs
E. Incomplete dominance will result in a ratio of 9 black : 3 brown : 4 yellow Labs
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