Deafness Is Caused by Recessive Mutations in Any One of at Least

Multiple Choice

Deafness is caused by recessive mutations in any one of at least five genes. Two deaf individuals have nine children, all of whom have normal hearing. Which of the following can you conclude?

A) The parents have mutations in the same gene.
B) The parents have mutations in different genes.
C) An epistatic interaction has occurred.
D) The mutations are codominant to the normal allele.
E) The mutations are incompletely dominant to the normal allele.