What is the genotype of the first female in the second row? (II, 2) Is spinocerebellar ataxia a dominant or recessive trait? If the male indicated by the arrow (III, 4) were to have a child with a woman who is a carrier for the disorder, what is the chance that their first child would have the disorder? Consider the following pedigree for spinocerebellar ataxia, a genetic disorder affecting the central nervous system..