Genetics Problems #1

1. The Gene for tall is dominant over dwarf in the garden pea plant used by Mendel. A pea plant that comes from a line of plants that are all tall is crossed with a dwarf pea plant. What is the phenotype of the Fl generation? What is (are) its genotype(s)?

2. If the offspring generation of problem 1 is crossed with the tall plant from a tall lineage, what will be the phenotype(s) and in what ratios for the offspring? What will be the genotype(s) and in what ratios?

3. If the Fl generation of problem 1 is crossed with the dwarf parent from a dwarf lineage, what will be the genotypes and the ratios of the offspring, and the phenotypes and ratios of the offspring?

4. The genes for dark eyes (black and brown) usually dominate over genes for blue or gray eyes. A man with black eyes marries a woman with light gray eyes. They have two children, a boy with black eyes, and a girl with blue eyes. What are the genotypes of the man, his wife, the little boy, and the little girl?

5. Assume that blood type is inherited as A and B dominant over 0, but A and B incompletely dominate over each other. Genotypes AA and AO are then phenotypically type A, genotypes BB and BO are type B, genotype AB is type AB, and genotype 00 is type 0 blood. A man with type A blood marries a woman with type A blood. They have the first child as blood type 0. What are the genotypes of the father, mother, and baby?

6. A man with a dimple and brown eyes (whose father had blue eyes but no dimples) marries a woman with a dimple and brown eyes (whose father had blue eyes with no dimple). What is the probability their first child will be blue-eyed and without a dimple? (Assume that dimple is a dominant over smooth cheeks, and brown eyes are dominant over blue).

7. A blue-eyed woman with no dimple marries a man with brown eyes and a dimple (whose mother had blue eyes and no dimple). What is the probability that their first child will have blue eyes and a dimple?