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Unformatted text preview: In our metapopulation example above, on the left all demes have p = 0.5 and the allele frequency for the entire array is also p = 0.5. Right away you can se that there in no differentiation among demes. To quantify this we use Fst which is calculated as Fst = (Ht - mean Hs) / Ht , where Ht = 2 (pooled p) (pooled q) [note that pooled q = (1-pooled p)], and mean Hs = the average of H values for each of the individual demes (i.e., 2 p q for each deme, averaged across all demes). For the left-hand metapopulation Ht = 2(0.5)(0.5) = 0.5, and mean Hs = 0.5 also. Thus , Fst = (0.5 - 0.5) / 0.5 = 0.0. What does this mean? In English this says that none of the variation in this system of demes lies between demes; the population structure is zero. Since there is variation (i.e., p _ 0) all of the variation lies within demes. Now consider the metapopulation system on the right above. The pooled allele frequency is 0.5 because half of the demes are fixed for the A allele (p = 1.0) and half are fixed for the a allele (p = 0.0). Hence the Ht value is 2 (pooled p) (pooled q) = are fixed for the a allele (p = 0....
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This note was uploaded on 11/05/2011 for the course BIOLOGY MCB2010 taught by Professor Jessicadigirolamo during the Fall '10 term at Broward College.
- Fall '10