Download Hardy Weinberg Equilibrium Problems

Hardy Weinberg Equilibrium Problems
Directions: Work the following problems on your own paper. Place your answers in the space provided
on this worksheet. Staple the paper showing your work to this sheet to turn in. SHOW ALL WORK!!!
You may assume that all the following populations are in equilibrium to begin with. NO WORK, NO
CREDIT, NO KIDDING!!!!
1. The frequency of two alleles in a gene pool is .1 (A) and .9 (a). What
is the:
a. frequency of the heterozygous individuals in the population?
b. frequency of the homozygous recessive individuals in the
population?
__________________________
__________________________
2. Allele W, for white wool, is dominant to allele w for black wool. In a
sample of 900 sheep, 891 are white and 9 are black. Calculate the allelic
frequencies for:
a. p
b. q
__________________________
__________________________
3. The frequency of the recessive homozygote genotype of a certain
trait is .09. What is the percentage of individuals homozygous for the
dominant allele?
__________________________
4. 36% of the individuals are recessive homozygotes for a certain trait.
For the same trait, what is the percentage in this population of:
a. homozygous dominant individuals?
b. heterozygous individuals?
c. homozygous recessive individuals?
__________________________
__________________________
__________________________
5. Allele T, for the ability to taste a particular chemical, is dominant to
allele t, for the inability to taste it. At Cornell University, out of 400
surveyed students, 64 were found to be non-tasters. What is the
percentage of heterozygous individuals?
__________________________
6. In humans, Rh-positive individuals have the Rh antigen in their
blood plasma while Rh-negative individuals do not. Assume that the
Rh-positive phenotype is produced by a dominant gene Rh, and the Rhnegative phenotype is produced by its recessive allele rh. If 84% of the
individuals are Rh-positive, what are the frequencies of the:
a. Rh allele?
b. rh allele?
__________________________
__________________________
7. In corn, yellow kernel color is controlled by a dominant allele; white,
by its recessive allele. A random sample of 1000 kernels from a
population reveals that 910 are yellow and 90 are white.
What are the frequencies in this population of the:
a. yellow alleles?
b. white alleles?
What is the percentage in this population of:
c. the heterozygotes?
__________________________
__________________________
__________________________
8. A rare disease, which is due to a recessive allele that is lethal when
homozygous, occurs with a frequency of one in one million. How many
individuals in a town of 14,000 can be expected to carry this allele?
__________________________
9. There are two alleles for a certain gene, A and a. The frequency of A
is 80%. What percentage of the population will be heterozygous for this
gene?
a. 4%
b. 16%
c. 32%
d. 64%
e. 100%
__________________________
10. In a peppered moth population, the allele for light color is recessive
and the allele for dark color is dominant. If there are 640 light moths,
and 360 dark moths, how many of the moths are heterozygous?
a. 96%
b. 64%
c. 48%
d. 32%
e. 8%
11. Sickle-cell anemia is a disease caused by the inheritance of a
dominant sickle gene. This gene is codominant with the normal
hemoglobin gene. In a certain African tribe, 4% of the population is
born with sickle-cell disease having inherited both dominant
sickle genes. What is the percentage of individuals in this tribe who
enjoy the selective advantage of the sickle-cell gene (advantage through
resistance to malaria) without all the symptoms of sickle-cell disease
(heterozygotes)?
12. In the United States, approximately one child in 10,000 is born with
PKU (phenylketonuria), a syndrome that affects individuals
homozygous for the recessive allele. What is the frequency of:
a. the PKU allele in the population?
b. the normal allele?
What is the percentage of the population of:
c. carriers of this trait?
13. In a population of 200 mice, 98 are homozygous dominant for
brown coat color (BB), 84 are heterozygous (Bb), and 18 are
homozygous recessive (bb). What are the frequencies for:
a. the alleles in this population?
b. the genotypes of this population?
14. Two Siamese cats and 3 Persians survive a shipwreck and are
carried on driftwood to a previously uninhabited tropical island. All five
cats have normal ears, but one carries the recessive allele for folded ears
(his genotype is Ff). What are the frequencies of allele F and allele f in
the population of this island?
a. F = .8, f = .2
b. F = .9, f = .1
c. F = .1, f = .9
d. F = .2, f = .8
e. none of these
15. In the above problem, about how many cats would you expect to
have folded ears when the island population reaches 20,000?
a. 0
b. 20
c. 200
d. 1000
e. 2000
__________________________
__________________________
__________________________
__________________________
__________________________
__________________________
__________________________
__________________________
__________________________
16. The allele frequencies in a population are A = 0.6, and a = 0.4.
Predict the genotypic frequencies for the next generation.
__________________________
17. Suppose that one gene locus determines stripe pattern in skunks. SS
skunks have two broad stripes; Ss skunks have two narrow stripes; ss
skunks have white speckles down their backs. A sampling of a
population of skunks found 65 broad-striped skunks, 14 narrow-striped
and 1 speckled. Determine the allele frequencies of:
a. p
b. q
__________________________
__________________________
18. In a population with 2 alleles for a particular locus, B and b, the
allele frequency of B is 0.7. What would be the frequency of
heterozygotes?
__________________________
19. In a population, 16% of the individuals show the recessive trait.
What is the frequency of the:
a. dominant allele?
b. homozygous dominant genotype?
c. heterozygous genotype?
d. dominant phenotype?
__________________________
__________________________
__________________________
__________________________
20. Of the members of a population of pea plants, 9% are short
(recessive). What are the frequencies of the:
a. recessive allele?
b. dominant allele?
c. genotypes?
__________________________
__________________________
__________________________
21. If p2 = 0.36, what percentage of the population has the recessive
phenotype?
__________________________
22. 4% of the members of a population of pea plants are short
(recessive). What are the frequencies of the:
a. recessive allele?
b. dominant allele?
c. genotypes?
__________________________
__________________________
__________________________
23. In Drosophila, the allele for normal length wings is dominant to the
allele for vestigial wings. In a population of 1,000 individuals, 360
show the recessive phenotype. How many individuals would you
expect to be:
a. homozygous dominant?
b. heterozygous?
__________________________
__________________________
24. The allele for the ability to roll one's tongue is dominant to the allele
for the lack of this ability. In a population of 500 individuals, 25% show
the recessive phenotype. How many individuals would you expect to
be:
a. homozygous dominant?
b. heterozygous?
__________________________
__________________________
25. The allele for the hair pattern called "widow's peak" is dominant to
the allele for no widow's peak. In a population of 1,000 individuals, 510
show the dominant phenotype. How many individuals would you expect
of the:
a. homozygous recessive genotype?
b. homozygous dominant genotype?
c. heterozygous genotype?
__________________________
__________________________
__________________________
BONUS FOR THE GIFTED.....
I. In white human beings, hair straightness of curliness is thought to be
governed by a single pair of alleles showing incomplete (partial)
dominance. Individuals with straight hair are homozygous for the S
allele, while those with curly hair are homozygous for the C allele.
Individuals with wavy hair are heterozygous. In a population of 1000
individuals, 245 were found to have straight hair, 393 had curly hair,
and 362 had wavy hair.
a. Give the allelic frequencies of the S and C alleles.
b. Is this population in equilibrium?
__________________________
__________________________
II. In poultry, the autosomal gene FB produces black feather color and
another allele, FW produces white feathers. The heterozygous condition
produces blue Andalusian. A white hen is mated to a black rooster and
the F2 were found to contain 78 black, 206 blue, and 116 white
chickens.
a. What are the frequencies of the black and white alleles?
b. Is the population in equilibrium?
__________________________
__________________________