Name______________________
Miss Badean
Date_________
AP Biology
Hardy-Weinberg Practice Questions
1. A population of rabbits may be brown (the dominant phenotype) or white (the recessive phenotype) The
frequency of the recessive allele in the population is 20%.
a. What is the frequency of the dominant allele? (p)
b. In a population of 2,000 rabbits, how many would you expect to be:
-Homozygous Dominant:
-Heterozygous:
Homozygous Recessive:
2. If 90 out of 200 individuals in a population express the recessive phenotype, what percent of the population
are heterozygotes?
3. 1 in 1700 US Caucasian newborns have cystic fibrosis. C is the normal allele, dominant over the recessive c
allele. Individuals must be homozygous for the recessive allele to have the disease. Assuming Hardy-Weinberg
equilibrium, approximately how many newborns would have cystic fibrosis in a population of 10,000 people?
ANSWERS:
1a. 0.8
1b. Homozygous Dominant: .64 x 2000 = 1280
Heterozygous: .32 x 2000 = 640
Recessive: .004 x 2000 = 80
2. 38.48% (110/200 = q^2 -> q = .74 - > p = .26 - > 2pq x 100 = 38.48%
3. 5.88 newborns (approximately 6) (1/1700 = q^2 -> q^2 x 10,000 = 5.88)