Solutions For An Introduction to Genetic Analysis Chapter 3 Problem 51P

a) The unusual feature which distinguishes this pedigree from other pedigrees is that maternal inheritance is seen. The disease seen in the mother is passed on to the sons and daughters. The sons do not pass the defective allele to their offspring while the daughters pass on the allele to all their offspring.

b) The mutant DNA responsible for this phenotype is likely to be present in the mitochondria. Since mitochondrial diseases are usually maternally inherited, we can say that this DNA is present in the mtDNA.