Name: ______Date: ______
Punnett Square Test
1. Saguaro cacti have two L-shaped arms, one on each side. Having both arms the same length is dominant over having two different length arms. A cactus that is homozygous for same length arms is crossed with a cactus with different length arms.
2. The x-linked barred locus in fruit flies controls the pattern of the wings, with the alleles (B) for barred pattern and (b) for no bars. A male with barred wings is mated to a non-barred female. Complete a punnett square to show the expected genotypes and phenotypes of the offspring. What are the odds of producing a barless female? A barless male?
3. In radishes, two incompletely dominant genes control color and shape. Red and white radishes are homozygous, whereas the hybrid is purple. Long and round radishes are homozygous and if crossed will produce an oval hybrid. Complete a punnet square to show the genotypes and phenotypes produced by crossing pure breeding red oval radishes with white round radishes.
4. A women with type A blood has a child with type O blood. She is suing a man with type B blood for child support, because she claims that man is the father of her child. How would you respond to the following statements. The attorney for the alleged father claims "The mother's blood is type A, so the child's type O blood must have come from the father. Because my client has type B blood, he can not be the father." The attorney for the mother claims "Because further tests prove he is heterozygous, he must be the father." Use Punnett squares to show which attorney is right if either. Discuss your results.
5. In crocus flowers, white and purple colors are co-dominant, and result in a purple and white striped flower when both genes are present. What are the possible results from the cross-pollination of a striped crocus with a striped crocus?
7. Lauren, who has blood type AB, marries Sal who has type B blood but whose mother has type O.
a. List the genotypes of Lauren, Sal and Sal's mother.
b. What are the percent possibilities for the blood type of their offspring.
8. One breed of cattle can be red, white, or roan (both red and white). The cross between 2 roans produces equal number of red and white progeny and twice as many roans., If a farmer wanted to breed an all roan herd, what animals should be the parents?
9. If a pea plant that is heterozygous for round, yellow peas is crossed with a pea plant that is homozygous for round peas but heterozygous for yellow peas, how many different phenotypes are their offspring expected to show?
10. In some cats the gene for tail length shows incomplete dominance. Cats with long tails and cats with no tails are homozygous for their respective alleles. Cats with one long tail allele and one no tail allele have short tails. Cross 2 short tail cats.