Download Simple Mendelian Genetics Problems

Name ________________________________________________ Date __________________ Per: ______
AP Biology Genetics Problem Set
Simple Mendelian Genetics Problems
In peas, seeds may be round (R) or wrinkled (r).
1.
What is the GENE? ____________________________
What is the dominant trait? ____________________________ What is the dominant allele (letter)? _____
What is the recessive trait? _____________________________ What is the recessive allele (letter)? _____
What proportion of the offspring in the following crosses would probably be wrinkled?

RR x rr

Rr x Rr

Rr x rr
Monohybrid Crosses
2. In men, brown eyes (B) is dominant over blue eyes (b). (The actual genetic situation is not this simple
but for this situation we will consider it simple Mendelian inheritance.) The gene is autosomal.
What is the GENE? ____________________________
What is the dominant trait? ____________________________ What is the dominant allele (letter)? _____
What is the recessive trait? _____________________________ What is the recessive allele (letter)? _____
a.
A heterozygous brown-eyed woman marries a blue-eyed man. What will be the genotypes and phenotypes of
their offspring?
b.
The first child of 2 brown-eyed parents has blue eyes. What are the genotypes of the 3 people? What other
phenotypes, and in what proportion, might be expected in future children?
AP Genetics Problem Set
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Name ________________________________________________ Date __________________ Per: ______
3.
Among Hereford cattle there is a dominant allele called polled; individuals with this allele lack horns. After college, you
become a cattle baron and stock your spread entirely with polled cattle. You personally check each cow to be sure that
none possess horns, and none do. Among the calves that year, however some grow horns. Angrily you dispose of them
and check to see that no horned adult has gotten into your pasture. None has. And yet the next year, more horned
calves are born. What is the source of your problem?
What is the GENE? ____________________________
What is the dominant trait? ____________________________ What is the dominant allele (letter)? _____
What is the recessive trait? _____________________________ What is the recessive allele (letter)? _____
4. The allele for axial flowers in peas is dominant to the allele for flowers borne terminally. What phenotypic
ratios would you expect among the offspring of a cross between a known heterozygous axial-flowered plant
and one whose flowers were terminal?
What is the GENE? ____________________________
What is the dominant trait? ____________________________ What is the dominant allele (letter)? _____
What is the recessive trait? _____________________________ What is the recessive allele (letter)? _____
5. Sniffles, a male mouse with a colored coat, was mated with Esmerelda, an alluring albino. The resulting litter
of 6 young all had colored fur. The next time around, Esmerelda was mated with Whiskers, who was the same
color as Sniffles. Some of Esmerelda’s next litter were white. Explain.
What is the GENE? ____________________________
What is the dominant trait? ____________________________ What is the dominant allele (letter)? _____
What is the recessive trait? _____________________________ What is the recessive allele (letter)? _____
AP Genetics Problem Set
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