1. Answer the following problems, showing all work; you will not receive credit for
the correct answers unless you show the work.
1. In mice, brown coat color is dominant over white coat color. Suppose two
heterozygous brown mice are crossed. What proportion of the offspring will be
2. In peas, purple flower color is dominant over white. Suppose a homozygous
purple plant is crossed with a white plant. Will there be any white offspring?
3. In humans, tongue rolling is a dominant trait. A man who cannot role his
tongue marries a woman who is homozygous for the tongue rolling trait. What
percentage of their children would be able to roll their tongue?
4. Freckles is a dominant trait. A woman homozygous for Freckles marries a man
without freckles. How many of their children are likely not to have freckles?
5. Smooth seeds are dominant to wrinkled seeds in pea plants. Two plants with
smooth seeds are crossed. Some F1 plants are wrinkled. What were the
genotypes of the parents? Show the punnett square to support your work.
Hint…this one is a little harder…you need to use the offspring to
determine the genotypes of the parents…you may need to do a couple
of punnett squares to arrive at the correct answer.