Chapter 7, Problem 21P

Albinism in animals is caused by recessive mutations in an autosomal gene required for synthesis of melanin, a chemical precursor for skin and eye pigments. Albino animals are often confused with so-called leucistic animals that are white due to recessive mutations in a gene required in a different pathway, for example a pathway for development of the cells that produce all skin pigments. Suppose you have two white hummingbirds-

a male and female—and they mated. Assuming that all relevant mutations are rare, autosomal, and recessive to wild-type alleles, what would you expect their progeny to look like under the following conditions:

a.	They are both albinos.
b.	They are both leucistic.
c.	One is albino and the other is leucistic.