Concept explainers
Albinism in animals is caused by recessive mutations in one of several autosomal genes required for synthesis of melanin, a chemical precursor for many 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 have 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. | They are both leucistic. |
c. | One is albino and the other is leucistic. |
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