Assignment 3

One of the conditions required for maintaining Hardy-Weinberg equilibrium in a population is random mating. When individuals select mates with a particular heritable trait—for example, color or size—this is a form of nonrandom mating known as assortative mating. Similarly, inbreeding is another form of nonrandom mating in which closely related individuals within a population mate. In this experiment, you will examine how different forms of mating among moths influence Hardy-Weinberg equilibrium. Working within PopulationGeneticsLab and referring to the detailed instructions on Assignment 3, answer the questions below.


1 .		Set up an experiment at default conditions for Hardy-Weinberg equilibrium for all parameters except the number of tree stands. Set tree stand number to 100. Carry out the first experiment with random mating. Then conduct a number of experiments where there is assortative mating. Use the slider to choose different degrees of assortative mating in values ranging from 0% (random mating) to 100% (only like phenotypes mate). What is the effect of assortative mating on genotype frequencies? Allele frequencies? Heterozygosity? Explain your answers.

2 .		Compare the effects of assortative mating to those of genetic drift (you will need to carry out additional experiments to complete this assignment). Carry out experiments similar to those that you did for genetic drift, but change mating to different degrees of assortative mating. How do the effects of assortative mating compare to those created by genetic drift? In particular, are the effects of assortative mating and the effects of genetic drift the same at different population sizes? Why or why not? Explain any differences you encountered between population size and the effects of assortative mating, and population size and the effects of genetic drift.

3 .		Conduct a series of experiments where there is disassortative mating. Choose different degrees of disassortative mating at values between 0% (random mating) and 100% (only unlike phenotypes mate). What is the effect of disassortative mating?

4 .		For both assortative and disassortative mating, conduct more experiments where you vary the initial genotype frequency. Try experiments where the initial allele frequency is not equal to 0.5. Based on the results of these experiments, can you draw any other conclusions about the effects of assortative and dissassortative mating on allele frequency?