Practice Pedigrees

Solution 4

The trait is also not Y-linked because females are affected. Female don't have Y chromosomes.

The trait also cannot be X-linked recessive. Affected daughters must have affected fathers. Affected person II-2 does not have an affected father (I-2).

This trait also cannot be autosomal recessive. Two affected parents must have 100% affected children. Parents II-2 and II-3 have an unaffected child (III-6).

This trait also cannot be X-linked dominant. An unaffected daughter must have an unaffected father. Child III-6 doesn't have an unaffected father (II-4).

This leaves autosomal dominant.