Synthesis Notes

What is an example of migrationselection balance

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Unformatted text preview: A2 and A2 to A1 and no other evolutionary forces are acting…it will eventually reach an equilibrium (1/2).  ­ If one is twice as large as the other:  ­ P* would be 2/3. (2v/3v)  ­ Q* would be 1/3 (1u/3u)  ­ Mutation will push us towards a frequency rate.  ­ Under H ­W, frequencies stay the same.  ­ If they are deleterious mutations, we expect recurring mutation to go up. If mutation rate increases, it increases the allele frequencies.  ­ If selection is increased, we expect the opposite to happen. It goes down. In a mainland ­island model, what qualitative effect does migration from the mainland have on allele frequencies on the island? • The change in allele frequencies on the island is directly proportional to the number of migrants who come to the island each generation and also to the difference between the beginning and ending allele frequencies on the island after migration. • We expect allele frequencies on the island to change until they match the frequency of the mainland 13 How does migration interact with selection? • Different populations of the species have different selective pressures, so some may be deleterious in one population and yet advantageous in another. What is an example of migration ­selection balance? • Variation of morphology of snakes in the Great Lakes ­ mainland vs. islands unbanded vs. banded What is genetic drift? • the change in the frequency of a gene variant (allele) in a population due to random sampling. • Book—random fluctuation in allele frequencies over time due to sampling effects in finite populations Why does it happen?  ­ To introduce...
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This note was uploaded on 05/18/2013 for the course BIOL 3040 taught by Professor Staff during the Spring '08 term at LSU.

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