In humans, the allele for the dimple trait is dominant over the allele for the non dimple trait, and the allele for the cleft chin trait is dominant over the allele for the non cleft chin trait. Mr. Smith has heterozygous alleles for both traits and exhibits dimples and a cleft chin. Mrs. Smith does not have dimples, nor does she have a cleft chin. The alleles for dimples are D and d, and the alleles for cleft chin are C and c.