Bio4250 – Evolutionary Genetics  HOMEWORK QUESTIONS   27 Nov 20209 Prepare answers to all of the following questions. You are encouraged to work in pairs; bear in mind that you are responsible for the accuracy of your own answers. For the Final Exam, I will select SIX of the questions: you must answer any FOUR of these. You are encouraged to use the Excel spreadsheet programs; Show your work. [Specific numbers in these problems may be changed] 

1. 2. The two graph below are simulations of allele A, where f(A)=q. What selection scheme is shown in each?

a. Strong selection against a recessive alleleb. Weak selection against a recessive allele

c. Strong selection against a dominant alleled. Weak selection against a dominant allele

What are the characteristics of the curves that tell you this? 

3. The four graphs below are MATLAB simulations of genetic drift under different conditions.(a) Which graph (LEFT or RIGHT) is likelier to have the larger starting population ? Explain(b) Which graph (LEFT or RIGHT) is likelier to have gone for the longer number of generations? Explain

4. Consider a population that undergoes a severe population reduction from 10,000 individuals to 100 individualsonce every 100 generations. Estimate the effective population size Ne over this 100 generations period.

5. The three grey boxes below represent three separate populations, with three sub‐populations each. In eachcase, “local F” is the inbreeding coefficient calculated for each sub‐population. For each problem, explain whatthe value of FST says about the structure of the population. Use the Excel spreadsheet.

6. From the following matrix of sequence differences, calculate by hand a UPGMA phenogram.Label the pairwise differences at all nodes.

7. Identify all Phylogenetically Informative Sites for species W, X, Y, & Z. Which species is most closely related to W?

8. Explain why each of the four types of sites 1, 2, 3, & 4 are uninformative. SHOW that positions of types 1,2, 3, & 4 require 0, 1, 3, & 2 nucleotide changes, respectively, for any of the three hypotheses above.

Four taxon problem is at [https://www.mun.ca/biology/scarr/Bio4250_-_Cladistic_dataset.html]

9. For the mutation model at

[https://www.mun.ca/biology/scarr/4250_Mutation-Selection_equilibrium.html]

If the mutation rate for the recessive condition Trumphair is 2 x 10-5 / gamete, and persons with Trump Hair hav

e a fitness W = 0.6, what is the equilibrium frequency of the allele for Trumphair?

10. For the migration model described at

[https://www.mun.ca/biology/scarr/4250_Migration-Selection_equilibrium_2020.html]

If q = 1.0 on the mainland, the migration rate from the mainland to the island is m = 0.1, and the fitness

of BB homozygotes on the island is W = 0.8, calculate the equilibrium frequency of q on the island.

11. In the pedigree shown at

[https://www.mun.ca/biology/scarr/4250_Inbreeding_&_Natural_Selection.html]

Show graphically that individual #10, the product of a first‐cousin marriage, has F = 1/16.

12. Based on the Genetic Drift model at [http://www.mun.ca/biology/scarr/4250_Genetic_Drift.html],

And the MatLab program, find a set of conditions of N and s2 in which one or more populations go to

fixation (q = 1) of an allele that is at a selective disadvantage. Explain how this happens.

13. At [http://www.mun.ca/biology/scarr/4250_F‐statistics.html], two ways of calculating FST are shown, in

terms of FIT & FIS  or HT & HS. Show that the two calculations are equivalent.