Application Punnett Squares
Side 1
Name:
Complete the following problems on this paper. Do not use a separate sheet.
Use the capital letter B for dominant and the lowercase letter b for recessive
for all problems on this side.
You are a dog breeder and want to get certain traits in your dogs offspring.
Determine what cross you would use to get certain traits to show through.
Make sure you carry out punnett’s square for each problem.
1.
You have three customers that have ordered dogs. Two of the customers
have ordered dogs with blue eyes and one ordered a dog with brown eyes.
If brown is dominant over blue determine what cross would give you the
best possibility of getting the correct offspring that will fill the orders.
Use punnett’s square to find the genotype and phenotype.
2.
There are four new orders for the month of May. These customers want
certain colored dogs. Three of the customers want black coats and one
wants a gray coat. If black is dominant over gray what would be the best
cross to fill the orders. Use punnett’s square to find the genotype and
phenotype.
3. There is breeder who wants to buy four dogs that can breed blue eyes or
brown eyes. If brown eyes are dominant over blue what is the best cross
that will fill this order. Use punnett’s square to find the genotype and
phenotype.
Side 2
Complete the following problems on this sheet of paper. Use the capital letter
D for dominant and the lowercase letter d for recessive for all problems on
this side.
4. If the trait for widows peak is recessive to the trait for a straight hairline
predict the genotype and phenotype for a cross between a hybrid straight
hairline and a purebred widows peak.
5. Sickle-cell anemia is a recessive inherited disease. If the mother had the
disease and the father did not have the disease, but knows that he carries
the trait, predict the genotype and phenotype for the offspring of the two
parents.
6. If neither brown or blue eyes are dominant predict the phenotype and
genotype of a cross between a purebred blue eyed parent and a purebred
brown eyed
parent.
Skip #6
7. PKU is a recessive disease that prevents an enzyme in the liver from being
produced. This enzyme is needed to break down certain chemicals in food.
The chemicals build up and may cause brain damage or mental disabilities.
If neither the father or mother have the disease, but are both carriers of
the disease predict the phenotype and genotype of the offspring. Also,
explain what percentage of their offspring will have the disease and what
percentage of the offspring will not.