Genetics Problem Set
Please complete the problems below using your lecture notes, study guides, and textbook as references..
1. (8 points) Use the following information to complete this question.
In guinea pigs, fur color is controlled by one gene. The gene has two alleles, symbolized B and b. A cross between two guinea pigs is shown below. The phenotype of each parent is indicated. The phenotypes of their offspring is also shown, along with the phenotypic ratio of offspring with black fur to those with brown fur.
P generation male with black fur x female with black fur
F1 generation 3 offspring with black fur: 1 offspring with brown fur
What is the character in this cross? __________________________
What are the traits? ______________________________________
What is the recessive phenotype? ___________________________
The male parent is crossed to one of his brown-furred daughters. Draw a Punnett square in the space below, showing the possible genotypes for the offspring of this second cross.

For this second cross, what would be the ratio of offspring with black fur to those with brown fur?
____________
(12 points) In cats, blood type is determined by a single gene. This gene has two alleles, symbolized IA and iB. IA produces the trait of type A blood, and iB produces the trait of type B blood. (There is no type O blood in cats.) IA is dominant over iB.
Listed below are crosses between different pairs of cats. The phenotype for each parent and the number of kittens produced from each cross and their phenotypes are given. Use this information to predict the genotypes of the parents.

Use the allele symbols to write the parents' genotypes.
               Male Parent    Female Parent       Kittens

Cross I       Type A                Type B             4 with Type A, 3 with Type B
Genotype __________ __________
Cross II       Type B                Type B             6 with Type B
Genotype __________ __________
Cross III    Type B                Type A             8 with Type A
Genotype __________ __________
Cross IV    Type A                Type A             7 with Type A, 2 with Type B
Genotype __________ __________
Cross V       Type A                Type A             10 with Type A
Genotype __________ __________
Cross VI       Type A                Type B             4 with Type A, 1 with Type B
Genotype __________ __________

(6 points) In cats, fur color is produced by an X-linked gene with two alleles. The two alleles are symbolized XB and XO. XB produces the trait of black fur, and XO produces the trait of orange fur. The two alleles are codominant, so heterozygotes have both black and orange fur, a phenotype called tortoiseshell. The Y chromosome does not contain the fur color gene.
A tortoiseshell female has a litter of kittens with the following phenotypes:
1 orange male, 1 black male, 2 tortoiseshell females, 1 orange female
Use the allele symbols to give the genotypes for each of the following:
Female parent ______________
Male parent ______________
Orange male kitten ______________
Black male kitten ______________
Tortoiseshell kittens    ______________
Orange female kitten ______________

Genetics Problem Set Please complete the problems below using you...