Question 3
Narcolepsy is a sleep disorder found in some breeds of dogs. The gene linked to
narcolepsy has two alleles. Two dogs, both without narcolepsy breed and
produce a litter of four puppies: one male and one female with narcolepsy, and
one male and one female without narcolepsy
Which of the following identifies and explains the probability that another
puppy with the same parents will have narcolepsy?
0%, because the parents already have two puppies with narcolepsy
25%, because narcolepsy is a recessive trait
75%, because narcolepsy is a dominant trait
50%, because of the puppies from the first litter had narcolepsy