## Nature/description of genetic information: Evolution

Differential transmission of alleles/genes/genotypes due to natural selection

**Simulating Hardy-Weinberg Principles**

Go to http://vudat.msu.edu/hardy-weinberg/ - click on Hardy-Weinberg Simulator

To operate the simulator:

[See screen shot below]

**Population Genetics and Hardy-Weinberg Equilibrium:**

If none of the assumptions of the Hardy-Weinberg Equilibrium are violated, allele frequencies will not change. For this simulation, the computer is set to conduct matings according to the assumptions of the Hardy-Weinberg Equilibrium; that is, populations are large, mating is random, natural selection is not acting, mutations do not occur, and immigration and emigration do not take place. Convince yourself that allele frequencies and genotype remain stable through time under these conditions by doing the following:

Enter the value of p (a decimal fraction of 1.0), which is the frequency of the dominant allele. For the *dilute* trait [see Phenotype and Genotoype], this is the frequency of D. Click on the q box to show the proportion of the recessive allele – d. (q = 1.0 - p). At this point DO NOT check any of the features to the right of the *Starting values* boxes.

Detailed information by generation is provided on the right side of simulator. Type in the generation about which you want more information. Click on the "Get Info!" box. You will be presented with the proportions of each allele at that generation as will as the genotype proportions (RR, Rr and rr). These would represent the proportions of DD, Dd and dd gentotypes.

**Evolution: violation of Hardy-Weinberg principles**:

You can set several parameters for the population you wish to investigate:

- Population size between 1,500 and 5,000 individuals
- Initial dominant allele frequency (p)
- Number of generations up to 100

Chose which force of evolution (violation of the Hardy Weinberg equilibrium) you want to apply by clicking on the corresponding circle.

For Natural Selection:

Chose the proportion of the two alleles. Type in a natural selection force against the rr genotype, from 0% (no selective pressure) to 100% (extreme selective pressure). The population is very large (n = 10,000). Click on the "Go" button to determine frequencies of alleles for the next 100 generations.

For Genetic Drift:

Chose the proportion of the two alleles. Click on the "Go" button to see the effect of small populations (n = 100) on the proportions of alleles from generation to generation.

For Mutation:

Chose the proportion of the two alleles. Type in the percent mutation (0-100%) from the d allele (proportion represented by q) to the D allele (proportion represented by p). The population is very large.

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