13. I, II, III, IV
14. Recessive. The trait skips generations and appears in offspring of unaffected parents.
15. Husband and wife.
16. IV-1, IV-3
17. III-4, III-5
18. For individuals with Hitchhiker's Thumb (shaded): hh. For normal individuals: H? (Heterozygous or Homozygous dominant). Specifically, III-4 and III-5 must be Hh (carriers), as they have affected children. All other normal individuals are H? unless proven otherwise by having affected offspring.
19. a. Black feathers b. White feathers c. Genotypes: I-1: Aa, I-2: Aa, II-1: aa, II-2: aa, II-3: aa, II-4: A?, II-5: A?, II-6: A?, II-7: A?, II-8: A?, III-1: A?, III-2: A?, III-3: A?, III-4: aa, III-5: A?
Parent Tip: Review the logic above to help your child master the concept of pedigree genetics worksheet.