Labrador retrievers are black, brown, or yellow. in a cross of a black female with a brown male, results can be either all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies. how many genes must be responsible for these coat colors in labrador retrievers?

Generally Labrador retrievers are black, brown, or yellow. in a cross of a black female with a brown male, results can be either all black puppies, 1/2 black to 1/2 brown puppies, or 3/4 black to 1/4 yellow puppies. So there must be 2 genes responsible for these coat colors in Labrador Retrievers.