1. Tasmanian devils once inhabited most of present day Australia, but only an isolated population on the island of Tasmania has survived to present day. What process has likely affected Tasmanian devils as a result of this history?
2. Considering the principles of mutation, natural selection, and genetic drift do you expect adaptive evolution to occur more rapidly in small or large populations? What about non adaptive evolution? For each answer, please explain your reasoning.
3. In a natural population of outbreeding plants, the variance of the total number of seeds per plant is 16. From the natural population, 20 plants are taken into the laboratory and developed into separate true-breeding lines by self-fertilization-with selection for high, low, or medium number of seeds-for 10 generations. The average variance in the tenth generation in each of the 20 sets is about equal and averages 5.8 across all the sets.
Estimate the broad-sense heritability for seed number in this population.
4. You are studying the effect of directional selection on body height in three populations (graphs a, b, and c above).
(a) What is the selection differential? Show your calculation.
(b) Which population has the highest narrow sense heritability for height? Explain your answer.
(c) If you examined the offspring in the next generation in each population, which population would have the highest mean height? Why?
5. Dr. O'Connor asked his BIOL260 class what their height was and what their parent's heights were. He plotted that data in the graph below to determine if height was a heritable trait.
a. Is height a heritable trait? If yes, what is the heritability value?
b. If the phenotypic variation is 30, what is the variation due to additive alleles?
6. According to a recent study,1 out of 50,000 people will be diagnosed with cystic fibrosis. Cystic fibrosis can be caused by a mutant form of the CFTR gene (dominant gene symbol is F and mutant is f).
a. Using the rate of incidence above, what is the frequency of carriers of the cystic fibrosis allele for CFTR in the US?
b. In a clinical study, 400 people from the population mentioned in (a.) were genotyped for BRCA1 gene. Listed below are the results. Are these results in Hardy-Weinberg equilibrium? Use statistics to show whether or not they are.
BRCA1 genotype #of women
BB 390
Bb 10
bb 0
7. You are studying a population of 100 flowers that has two alleles at a locus for flower color, blue (B) and green (G). There are 15 individuals with the BB genotype, 70 individuals with the BG genotype, and 15 individuals with the GG genotype.
(a) What are the allele frequencies of B and G in the starting population? Show your calculations.
(b) Is this population in Hardy-Weinberg equilibrium? Show your calculations.
8. The relative fitnesses of three genotypes are wA/A= 1.0, wA/a= 0.7, and wa/a= 0.3
a. If the population starts at the allele frequency p = 0.5, what is the value of p in the next generation?
b. What is the predicted equilibrium allele (qˆ) frequency if the rate of mutation from A → a is 2 × 10-5?
9. In a population of Jackalopes, horn length will vary between 0.5 and 2 feet, with the mean length somewhere around 1.05 feet. You pick Jackalopes that have horn lengths around 1.75 feet to breed as this appears to be the optimal length for battling other Jackalopes for food. After a round of breeding, you measure the offsprings' mean horn length is 1.67. Is Jackalope horn length a heritable trait?