Animal Science
Punnet Square
Practice Problems
25 pts
Use the punnet square to predict genotypes and phenotypes of the following
matings; include ratios for both genotype and phenotype along with their
descriptions
1. A black stallion is crossed with a black mare. Both parents are heterozygous for
black.
Note: B = black, dominant
b = brown, recessive
a. what is the genotype of each parent? (1 pt)
b. what are the genotypes and phenotypes of the F1? (4 pts)
2. A horned ewe is crossed with a polled ram:
Note: H = dominant horned in male
h = dominant polled in female
HH = horned in both male and female
hh = polled in both male and female
a. what is the genotype of each parent? (4 pts)
b. what is the sex of the horned offspring? (2 pts)
3.
A black, white-belted pig is crossed with a red, non-belted pig. Black (B) is
dominant over red (b), and white-belted (W) is dominant over non-belted (w).
Assume each parent is homozygous for these traits. Show all work!
a. What is the genotype of each parent? (2 pts)
b. What are the genotype and phenotype of the F1 ? (3 pts)
c. What are the genotypic ratio, phenotypic ratio, and phenotype of the F2 ? (9 pts)