Manx cats have no tails.When two Manx cats are bred together there is always a one third chance that a kitten will have a tail.When a Manx cat is bred to a cat with a normal tail there is a one-half chance that a kitten will have a tail.Which of the following is the best explanation for this?
A)The Manx genotype exhibits variable expression.
B)The Manx phenotype is dominant,but the allele is a recessive lethal.
C)The Manx phenotype is dominant epistatic.
D)The Manx phenotype is caused by gene interactions.
E)The Manx phenotype is a result of heteroplasmy.

Question

Quizplus · Accepted Answer

The fact that a Manx cat bred with a normal-tailed cat has a 50% chance of producing kittens with tails suggests that the Manx phenotype is dominant. However, the fact that breeding two Manx cats together can result in a kitten with a tail suggests that the allele is recessive lethal, meaning that homozygous Manx cats do not survive to birth. Therefore, the Manx phenotype is dominant, but the allele is a recessive lethal.

Manx Cats Have No Tails