Human Heredity 11th Edition by Michael Cummings

Exercise 4

Familial retinoblastoma, a rare autosomal dominant defect, arose in a large family that had no prior history of the disease. Consider the following pedigree (the darkly colored symbols represent affected individuals):
A) Circle the individual(s) in which the mutation most likely occurred.
B) Is the person who is the source of the mutation affected by retinoblastoma? Justify your answer.
C) Assuming that the mutant allele is fully penetrant, what is the chance that an affected individual will have an affected child?