Hardy-Weinberg Problems
name___________________________hr__
Show work on separate paper & staple to back of this sheet.
1. In a population of 100 individuals 49% are of the NN phenotype. What
percentage is expected to be Nn assuming Hardy-Weinberg equilibrium?
A. 9%
B. 21%
C. 42%
D. 51%
E. insufficient information to answer question
2. Attached ears is an autosomal recessive trait in humans. Assume that there are
400 people with attached ears in a population of 10,000. How many individuals
would be expected to homozygous dominant?
A. 800
B. 100
C. 6400
D. 200
E. 10,000
3. In a population that meets the H-W equilibrium assumptions, 81% of the
individuals are homozygous for a recessive gene. What percentage of the
individuals would be expected to be heterozygous for this gene?
answer:
4. A farmer bought a herd of 600 sheep, taken from a freely breeding population, and later
found that 150 of the animals had an economically undesirable feature, crinkly-hair, caused by
the recessive allele c. What is the frequency of this undesirable allele in the herd?
answer:
B.What proportion of the herd is likely to be heterozygous?
answer:
5. The alleles for red and white coat color in cattle show incomplete dominance, the
heterozygote being roan. In a freely breeding herd of 1000 head how many would you expect
to be of each coat color if the allele for white coat has a frequency of 0.4?
answer:
Hardy-Weinberg Problems
name___________________________hr__
6. In a sample of 2400 births at a maternity hospital, six babies died shortly after birth from
the effects of a recessive gene (c) for colonic obstruction.
A.What is the frequency of this gene in the population?
answer:
B.What proportion of the population is heterozygous and what proportion is homozygous for
the normal allele?
answer:
For the next three problems calculate the frequency of the three genotypes. Also calculate the
hypothesized actual number of the genotypes and the phenotypes.
7. A herd of 300 cows (+ a few bulls) with 12 homozygous recessive individuals.
answer genotypes:
answer phenotypes
8. A school(?) of 86 sea cows includes 24 individuals which have a recessive skin disorder
causing them to be fluorescent yellow.
answer genotypes:
answer phenotypes:
9. A flock of 125 scarlet macaws that includes 15 individuals with gold colored feathers (a
recessive mutation).
answer genotypes:
answer phenotypes
Determine the allele frequency of the current group of individuals, calculate the expected
genotypic frequencies and the frequency of each phenotype.
10. A flock of 342 scarlet ibis that includes 102 individuals with green colored legs (a
dominant mutation).
answer: