Consider the following pedigree, which traces the inheritance of a single-gene hereditary disease. Only individuals that are either affected or normal are shown. In other words, potential heterozygotes are NOT indicated.

Characterize each of the following modes of inheritance as: impossible, unlikely, or probable. Justify your answers.

a.Autosomal dominant

b.Autosomal recessive

c.X-linked dominant 

d.X-linked recessive

e.Y linked