Chapter 3, Problem 19QP

More Crosses with Pea Plants: The Principle of Independent Assortment

Think about this one carefully. Albinism and hair color are governed by different genes. A recessively inherited form of albinism causes affected individuals to lack pigment in their skin, hair, and eyes. In hair color, red hair is inherited as a recessive trait and brown hair is inherited as a dominant trait relative to red hair. An albino woman whose parents both have red hair has two children with a man who is normally pigmented and has brown hair. The brown-haired partner has one parent who has red hair. The first child is normally pigmented and has brown hair. The second child is albino.

1. a. What is the hair color (phenotype) of the albino parent?
2. b. What is the genotype of the albino parent for hair color?
3. c. What is the genotype of the brown-haired parent with respect to hair color? Skin pigmentation?
4. d. What is the genotype of the first child with respect to hair color and skin pigmentation?
5. e. What are the possible genotypes of the second child for hair color? What is the phenotype of the second child for hair color? Can you explain this?