MicroEVO - MicroEVO Last updated Introduction This workbook...

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MicroEVO Last updated 3-31-2004 Introduction This workbook simulates what happens when any of the assumptions of the Hardy-Weinberg principle are broken: 1. Natural selection 2. Mutation 3. Migration 4. Genetic drift (which occurs when the population size is small) 5. Inbreeding (non-random mating) There are other assumptions required for the Hardy-Weinberg princple to work, but this workbook only allows you to manipulate the five listed above. You can simulate the effects of any one of these processes by itself or in conjunction with others. For example, you might see which is a more powerful process in evolution, natural selection or mutation. The workbook is composed of worksheets. At the bottom of this page you will see the name of the worksheets. The first one is labeled "Intro," and it is the worksheet you are on now. To get started, go to the "Input" worksheet and follow the instructions there. population over time, click the appropriate tab. Each process is simulated over 1000 generations, but sometimes it is hard to see sudden change if you look at a graph with all the generations from 0 to 1000. Each graph thus has two versions, one over 1000 generations, and one over 100 generations. They show the same data but over a different time period. For example, "Genotypes (1000)" displays the genotypic frequencies from generation 0 to 1000, and "Genotypes (100)" displays from generation 0 to 100. The population always starts in Hardy-Weinberg equilibrium. To see the graphs of genotypic frequencies or allelic frequencies of your
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Input Worksheet Instructions: Please only enter values in white cells like this… do not change other cells. Cells that have a sma have comments to hel move the cell to read t Initial allelic frequencies OK Initial frequency of allele A = 0.6 Initial frequency of allele a = 0.4 ← This value will adjust itself. Genotype AA Aa aa Initial frequency 0.36 0.48 0.16 Natural selection OFF Genotype AA Aa aa Selection coefficient 0 0 0 Typical values 0.01 0.01 0.00 Mutation OFF Mutation rate for A → a 0 Typical value seen in nature 0 Migration OFF Migration rate 0 Source population genotypes AA Aa aa Frequencies 0.6 0.2 0.2 Genotypic frequencies must sum to 1.00. Genetic drift OFF If your population is infinite, type "infinite". Otherwise, enter the number of individuals in your population. Adjust this value only.
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Population size = infinite Note: The method used to model drift is only approximate because it is a random process. Each time you enter a new number anywhere on the spreadsheet, new random numbers will be generated and your results will change. So, looking at just one trial is not enough. To run repeated trials, hit the F9 button. This recalculates the spreadsheet and generates a new set of random numbers. This simulation is not realistic for populations > 5000 (except infinity).
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