AP BIOLOGY

Detailed explanation-1: -Interestingly, the word “epistasis” is composed of Greek roots that mean “standing upon.” A good example of epistasis is coat color in the popular dog breed the Labrador retriever. Labrador retriever coat color genes only come in black or chocolate.

Detailed explanation-2: -Labradors of genotype E/-will have dark-colored fur (either black or brown) while yellow labradors have the recessive genotype e/e. Since having the genotype e/e will result in a yellow coat no matter whether the dog is B/-or b/b, carrying two copies of the e allele is recessively epistatic to the B gene.

Detailed explanation-3: -The system of genes that determines skin colour in man, for example, is independent of the gene responsible for albinism (lack of pigment) or the development of skin colour. This gene is an epistatic gene.

Detailed explanation-4: -Labrador Retriever Coat Color. Task-level Phenomena: In this lesson, the specific phenomenon is the coat color of Labrador Retrievers as an example of epistasis in this task.

Detailed explanation-5: -An example of epistasis is the interaction between hair colour and baldness. A gene for total baldness would be epistatic to one for blond hair or red hair. The hair-colour genes are hypostatic to the baldness gene. The baldness phenotype supersedes genes for hair colour, and so the effects are non-additive.