What is the chance that their offspring will develop sickle cell anemia?
Correct. A cross of Aa x aa produces 50% aa (who will develop the disorder) and
50% Aa (who will not develop the disorder).
A gene that encodes an enzyme required for ribose synthesis is found on the X
chromosome. Females that are heterozygous for the wild-type and defective
mutant allele of this gene will show: