Biology 11th Edition by Cecie Starr ,Ralph Taggart

تمرين 12

A gene encodes the second enzyme in a melanin-synthesizing pathway. An individual who is homozygous for a recessive mutant allele of this gene cannot produce or deposit melanin in body tissues. Albinism , the absence of melanin, is the result.
Humans and a number of other organisms can have this phenotype. Figure 11.21 shows two examples. In the following situations, what are the possible genotypes of the father, the mother, and their children
a. Both parents have normal phenotypes; some of their children are albino and others are unaffected.
b. Both parents are albino and have albino children.
c. The woman is unaffected, the man is albino, and they have one albino child and three unaffected children.