Question

Piebald spotting is a condition found in humans in which there are patches of skin that lack pigmentation. The condition results from the inability of pigment- producing cells to migrate properly during development. Two adults with piebald spotting have one child who has this trait and a second child with normal skin pigmentation. a. Is the piebald spotting trait dominant or recessive? What information led you to this answer? b. What are the genotypes of the parents?

Answer 1

Answer:

The autosomal trait are present on the autosomes and does not have any influence on the sex of the organism. Two main types of autosomal trait are autosomal dominant and autosomal recessive trait.

a. The trait discussed in the question must be the autosomal dominant trait. As the normal and affected children are produced by the affected parents cross. The appearance of the normal child determines that the trait is dominant.

b. Since both the parent are affected but the normal child has been produced from the cross. The parents must be heterozygotes for the trait, (Aa). Their cross will produce the progeny AA, Aa and Aa (affected) and aa (normal).