Biology: Concepts and Investigations 2nd Edition by Mariëlle Hoefnagels

Exercise 55

In humans, more than 100 forms of deafness are inherited as recessive alleles on many different chromosomes. Suppose that a woman who is heterozygous for a deafness gene on one chromosome has a child with a man who is heterozygous for a deafness gene on a different chromosome. Does the child face the general population risk of inheriting either form of deafness or the 25% chance that Mendelian ratios predict for a monohybrid cross? Explain your answer.