Or we could calculate it as 2* p-bar * q-bar Overall total population (using global allele frequencies and a modified form of Eqn 35.1): H Tbased on expected heterozygosities for Heterozygosities in individuals in subpopulations Note that the first two calculations employ a weighted average of the values in the whole set of subpopulations. Calculate the global heterozygosity indices (over Individuals, The check doesn't guarantee that our result is correct, but if they don't sum to one, we know we ( q-bar, the frequency of allele a) over the total population Check: Note that we weight by population size Step 7. Gene frequencies" step, or have one for each allele frequency]. Had more alleles we could put this and Step 7 all together as a single "global (p-bar, the frequency of allele A) over the total population. Where s ( s = 1 to 3) refers to the subpopulation Calculate the local inbreeding coefficient of each subpopulation (same as Eqn 35.4, except that we are Indeed, with real multi-locus multipopulationĭata, we would have a triple summation and three subscripts one for alleles ( i =1 to k), one for the loci ( l =1 to m), and one for subpopulations ( s = 1 to n). We would need to use multiple subscripts if we were using the notation of Eqn 35.1 where the alleles are p i (and the i Note that I am using p 1 and q 1 here (where the subscripts refer to subpopulations 1 through 3). (With two alleles it would actually be easier to use 2 pq than to use the summation format of Eqn 33.1) Notation: Calculate the local expected heterozygosity, or gene diversity, of each subpopulation (modified version of Eqn 35.1): Subscript refers to the s th of n populations Of each subpopulation (we will call them H obs s, where the s Calculate the local observed heterozygosities Homozygotes: outbred or experiencing a Wahlund effect (isolate Summary of homozygote deficiency or excess = 422.5 (observed has deficiency of 22.5) = 122.5 (observed has deficiency of 22.5) These quantities have to balance (it's a mathematical Note that sum of two types of homozygote excess Or deficiency of homozygotes in each subpopulation. Under Hardy-Weinberg Equilibrium, and then calculate the excess Note that the denominator willīe twice N i (twice as many alleles as individuals). Population 3: 1,000 Remember that the number of alleles is TWICEįrequencies: Each homozygote will have two alleles, Of each of the rows in the table above): Population 1: 500 Fst example Worked example of calculating F-statistics from genotypic data:
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