Punnett Squares Worksheet #3

Name: ______Period: ______Date: ______

1. In snapdragons, no color is dominant. Plants with two copies of one allele (RR) have red flowers, while plants with the other allele (WW) have white flowers. An intermediate (in between) phenotype occurs in hybrids (RW): pink flowers! a. What is the name for this mode of inheritance?

b. Cross a red snapdragon with a white snapdragon.

What will the genotype be for the offspring? ______

What will the phenotype be for the offspring? ______

RR = red WW = white RW = pink

c. Cross a pink snapdragon with another pink snapdragon.

What is the genotype ratio?

______

What is the phenotype ratio?

______

d. Two snapdragons were crossed and produced 1000 seeds. When they were planted, 498 of them had red flowers; 502 of them had pink flowers. What were the likely genotypes of the parent plants? Hint: work backwards! Name: ______Period: ______Date: ______

Punnett Squares Worksheet #5

2. Human blood types are determined by a single gene pair with three different alleles: A, B and O. Both the A and B alleles are dominant to O. A and B are codominant to each other. See the table below:

Genotype AA AO BB BO AB OO Phenotyp e A A B B AB O

a. A man with type AB blood marries a woman with type O blood.

What are the possible genotypes for their offspring?

______

b. Could a mother with type B blood and a father with type O blood produce offspring with type O blood? Hint: set up the two possible Punnett squares to solve this problem, given that more than one genotype can give the same phenotype.

What must the mother’s genotype be in order to have a child with type O blood (with this particular father)? ______Is she homozygous or heterozygous with respect to her blood type?