In rabbits, one enzyme (the product of a functional gene A) is needed to produce a substance required for hearing. Another enzyme (the product of a functional gene B) is needed to produce another substance required for hearing. The genes responsible for the two enzymes are not linked. Individuals homozygous for either one or both of the nonfunctional recessive allels, a or b, are deaf.
a. If a large number of matings were made between two double heterozygotes, what phenotypic ratio would be expected in the progeny?
b. This phenotypic ratio is a result of what well-known phenomenon?
c. What phenotypic ratio would be expected if the rabbits homozygous recessive for trait A and heterozygous for trait B were mated to rabbits heterzygous for both traits?