NAME:_____________________
More Practice Problems:
These problems are NOT due and the answers are posted online
1. Fred and Wilma have widow’s peaks. Their daughter Shirley has a straight hairline. (Widows
peak is dominant to straight hairline)
a. What are Fred and Wilma’s genotype? Fred:______________ and Wilma:____________
b. What is Shirley’s genotype? _____________
2. In dogs, wire hair is dominant to smooth.
a. In a cross a homozygous wire-haired dog with a smooth-haired dog, what will be the
phenotype of the offspring?
b. What would be their genotype?
c. IF you allow these offspring to mate, what would be the ratio of wire-haired to smooth
haired dogs in the next generation?
3. A couple is told that they are carriers for the disease cystic fibrosis.
a. What is the genotype of each parent? __________x______________
b. Complete a punnett square for this couple.
c. What is the chance that they will produce a child with cystic fibrosis?
d. What is the chance that they will have a child who is a carrier?
e. What is the chance they will have a child who has a normal phenotype and no chance of
passing the disease allele to children of their own?
4. Wolves are sometimes observed to have black coats and blue eyes. Normal coat color is
dominant to black and brown eyes are dominant to blue. Suppose the alpha male of a pack is
black with blue eyes and the alpha female is normal colored with brown eyes. The female is
heterozygous for both traits. How many of the offspring (assume 16) living in the pack will have
each of the following phenotypes?
a. What percent of the offspring will be normal colored with blue eyes?
a. What percent of the offspring will be black with blue eyes?
a. What percent of the offspring will be normal colored with brown eyes?
a. What percent of the offspring will be black with brown eyes?
5. A man who is blood type A and heterozygous marries a woman who is type B and heterozygous.
a. What is the chance that they will have a child with type O blood? Show your work.
b. What is the chance that they will have a child with type B blood? Show your work.
6. A man who is color blind marries a woman with normal vision who is homozygous. Show your work.
a. What will be true of their daughters?
b. What would be true of their sons?
7. A mother is a carrier for colorblindness and her husband is not colorblind.
a. What is the chance they will have a color blind son? Show your work.
8. Yellow and white-colored mice are homozygous, while cream-colored mice are heterozygous. If two
cream-colored mice mate, what phenotypic ratio can we expect of their offspring? Show the Punnett
Square.
Incomplete or co-dominance:__________________________________
9. In some chickens, the allele for black is B and the allele for white is W. The heterozygous phenotype is
known as erminette (black and white spotted).
a)
b)
c)
What is the genotype for black chickens? ____
What is the genotype for white chickens? ____
What is the genotype for erminette chickens? ____
10.
Two erminette chickens were crossed. Show the Punnett square.
a)
b)
What’s the probability they would have a black chick? ____%
What’s the probability they would have a white chick? ____%
11. A black chicken and a white chicken are crossed. Show the Punnett Square. What is the probability
that they will have erminette chicks? ____%
12. Are questions #9-11 an example of co-dominance or incomplete dominance?
13. In shorthorn cattle, when a red bull (RR) is crossed with a white cow (WW), all the offspring are
roan—a spotted, red and white or milky red color. What offspring are expected from mating a roan bull
and a roan cow? Show the Punnett Square.
For Questions 14-22, use the pedigree chart shown below. Some of the labels may be used more than
once.
________ 14. A male
15. A female
________ 16. A marriage
17. A person who expresses the trait
18. A person who does not express the trait
19. A connection between parents and offspring
________ 20. How many generations are shown on this chart?
Assuming the chart above is tracing the dominant trait of "White Forelock (F)" through the family. F is
a tuft of white hair on the forehead.
________21. What is the most likely genotype of individual “A”? (FF, Ff or ff?)
________22. What is the most likely genotype of individual “C”? (FF, Ff or ff?)
A typical pedigree for a family that carries Falconi anemia. Note that carriers are not indicated with halfcolored shapes in this chart.
1. What is Arlene's genotype?
2. What is George's genotype?
3. What are Ann & Michael's genotypes?
4. Most likely, Sandra's genotype is
.
5. List three people from the chart (other than George) who are most likely carriers of Falconi
anemia._____________________________________________________________