Practice Problems

1. Practice Problems SBI 3U: Test Review

2. Monohybrid Cross • In humans, brown eyes (B) are dominant over blue eyes (b). If a heterozygous brown-eyed man marries a heterozygous brown eyed woman, what are the possible genotypes and phenotypes for their offspring?

3. Monohybrid Cross • Cystic fibrosis (CF) is an recessive genetic disorder. If a man who is homozygous dominant marries a woman who is a carrier for cystic fibrosis, what are the possible genotypes and phenotypes for their offspring?

4. Monohybrid Cross • Huntington’s Disease is a dominant genetic disorder. If a man who isheterozygous for Huntington’s Disease, marries a woman who is homozygous recessive, what are the possible genotypes and phenotypes for their offspring?

5. Di-hybrid Cross • In horses, the coat color black is dominant (B) over chestnut (b). The trotting gait is dominant (T) over the pacing gait (t). If a homozygous black pacer is mated to a homozygous chestnut, heterozygous trotter, what are the possible genotypes and phenotypes for their offspring?

6. Di-hybrid Cross • In mice the ability to run normally is a dominant trait. Mice with this trait are called runningmice (R). The recessive trait causes mice to run in circles. Mice with this trait are calledwaltzing mice (r). Hair color is also an inherited trait in mice. Black hair (B) is dominant overbrown hair (b). • Cross a heterozygous running heterozygous black mouse with a homozygous running,homozygous black mouse. What are the expected phenotypes and genotypes of their offspring?

7. Incomplete Dominance • In Mountain Mice, the tail length trait exhibits incomplete dominance. What are the possible genotypes and phenotypes from a cross between a homozygous long tailed and homozygous short tailed mountain boomer?

8. Co-dominance • In dogs, gum coloration is co-dominant. A dog can have pink gums, black gums, or pink with black spots. What are the possible genotypes and phenotypes when a dog with pink gums is bred with a pink and black spotted gum dog?

9. Co-dominance • In shorthorn cattle, hair colour is decided by co-dominant traits. If a cow that has red hair is bred with a white hair cow, they produce roan offspring (both red and white hairs). What would the expected genotypes and phenotypes be when two roan cows mate?

10. Sex-linked Inheritance • Hemophilia is an X-linked recessive genetic disorder. A man who has hemophilia marries a woman who is homozygous dominant for the trait. What are the possible genotypes and phenotypes for their offspring?

11. Sex-linked Inheritance • Male patterned baldness is an X-linked recessive genetic trait. A bald man marries a woman who is a carrier for the trait. They find out they are having a baby girl. What is the probability that their daughter will go bald?

12. Multiple Alleles • A woman with heterozygous blood type A marries a man with blood type O. What are the possible genotypes and phenotypes of their offspring?

13. Multiple Alleles • A man with blood type AB marries a woman with blood type B. What are the possible genotypes and phenotypes of their offspring?