NOTE: This is not an assignment; it will not be graded. The exercises below were created to help you review some of the equations and concepts presented in class. They do not cover all the material that may be on the exam; they are just for practice.
1. A population of capybaras contains 104 individuals. Studying them you discover that they have two types of alleles for a certain gene. The frequency of the recessive allele (c) is 0.3 and we assume that this is an ideal population with simple dominance.
a) Calculate the frequency of the dominant allele, C.
b) Calculate the genotype frequencies in the next generation (F1)
c) Calculate the phenotype frequencies of F1
d) Calculate the heterozygosity (H)
e) Calculate the number of heterozygous individuals in the wild population
2. A biologist wanted to know more about this population of capybaras and discovered that 70% of the females (N = 40) and 40% of the males cannot breed (although the causes were not determined). Recall from question 1 that there are 104 total capybaras in the population, and assume a polygynous mating system.
a) Calculate the effective population size
b) How would assuming a monogynous
mating structure influence your calculations in part a?
c) Calculate the loss of heterozygosity per generation
d) Calculate the percent heterozygosity remaining after 7 generations
3. Below are the genotypes at three loci for a sample of 6 individuals
|
Individual |
Locus |
||
|
1 |
2 |
3 |
|
|
1 |
DD |
EE |
Ff |
|
2 |
DD |
EE |
Ff |
|
3 |
DD |
Ee |
ff |
|
4 |
DD |
EE |
FF |
|
5 |
DD |
EE |
FF |
|
6 |
DD |
Ee |
ff |
a) What are the allele frequencies for each locus?
b) What are the frequencies of genotypes for each locus?
c) What is the percent polymorphism (P) for this population?
d) What is the average heterozygosity (H-bar) for this population?
e) What would genotype frequencies be at locus 2 in this population if it were in Hardy-Weinberg equilibrium?
f) If individuals 1-3 were males and individuals 4-6 were females, what would be the effective population size of this population (all are breeders)?
g) What portion of the genetic variance of this population would be likely to remain after three generations of random genetic drift? (Use the effective population size calculated in the preceding question.)
4. In the plant species Grandi floria, most individuals have large flowers. However, plants that are homozygous recessive at the G allele have small flowers. If there are 75 plants with large flowers (G_), and 25 plants with small flowers (gg), calculate the following (assume Hardy-Weinberg equilibrium):
a) The frequency of alleles G and g
b) The genotype frequencies