Concept explainers
In humans, hemophilia A (OMIM 306700) is an X-linked recessive disorder that affects the gene for factor VIII protein, which is essential for blood clotting. The dominant and recessive alleles for the factor VIII gene are represented by H and h. Albinism is an autosomal recessive condition that results from mutation of the gene producing tyrosinase, an enzyme in the melanin synthesis pathway. A and a represent the tyrosinase alleles. A healthy woman named Clara (II-2), whose father (I-1) has hemophilia and whose brother (II-1) has albinism, is married to a healthy man named Charles (II-3), whose parents are healthy. Charles’s brother (II-5) has hemophilia, and his sister (II-4) has albinism. The pedigree is shown below.
a. What are the genotypes of the four parents (I-1 to I-4) in this pedigree?
b. Determine the probability that the first child of Clara and Charles will be a
i. boy with hemophilia
ii. girl with albinism
iii. healthy girl
iv. boy with both albinism and hemophilia
v. boy with albinism
vi. girl with hemophilia
c. If Clara and Charles’s first child has albinism, what is the chance the second child has albinism? Explain why this probability is higher than the probability you calculated in part (b).
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- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning