Name ______________________________________
AP Biology
Date ___________
/100 points
Hardy-Weinberg Practice Problems
1. A hypothetical population of 10.000 humans has 6,840 individuals with blood type AA,
2860 with blood type AB, and 300 individuals with blood type BB.
a. What is the frequency of the genotype AA?
b. What is the frequency of the genotype AB?
c. What is the frequency of the BB genotype?
d. What is the frequency of the A allele?
e. What is the frequency of the B allele?
f. If the next generation had 50,000 individuals, how many individuals would have
the blood type AB assuming Hardy-Weinberg equilibrium?
2. If 98 out of 200 individuals in a population express the recessive phenotype, what
percent of the population are heterozygotes?
3. Brown hair (B) is dominant to blond hair (b). If there are 168 blond-haired people in a
population of 200:
a. What is the predicted frequency of heterozygotes?
b. Homozygous dominants?
c. Homozygous recessives?
4. Normal homozygous individuals (SS) have normal blood cells that are easily infected
with malarial parasites. Individuals homozygous for the sickle-cell trait (ss) have sicklecell anemia. Individuals with the heterozygous condition (Ss) are generally protected
from malaria because the parasite cannot survive well within these “partially defective”
red blood cells. If 9% of an African population born with a severe form of sickle-cell
anemia (ss), what percentage of the population will be more resistant to malaria because
they are HETEROZYGOUS (Ss) for the sickle-cell gene?
5. Male-pattern baldness is a recessive trait encoded for by “b”. Non-balding is encoded for
by a dominant allele (B). A street survey conducted by Hair Club for Men found that out
of 1,000 men, 360 had male-pattern baldness, the other 480 who did not and were
heterozygous, and 160 who did not and were homozygous recessive for a full head of
hair.
a. What is the allele frequency for B?
b. What is the allele frequency for b?
c. What is the expected genotype frequency for BB?
d. Frequency for Bb?
e. Frequency for bb?
Name ______________________________________
AP Biology
Date ___________
/100 points
6. Tasting PTC is due to a dominant allele (T). You sample 215 individuals in a biology
class, and determined that 150 could detect the bitter taste of PTC and 65 could not.
a. What is the frequency of the recessive allele (t)?
b. What is the frequency of the dominant allele (T)?
c. What is the genotype frequency of heterozygotes?
d. In a population of 100,000 people, how many would be heterozygous (assuming
Hardy-Weinberg equilibrium)? Homozygous dominant? Homozygous recessive?