L41 BIOL 2970 Lecture Notes - Lecture 38: Upgma, Allele Frequency, Zygosity
17 Dec 2017
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Metapopulation -- large population subdivided geographically into many local demes. Gene flow -- movement of genes between demes m = fraction of a population that migrates to another one before mating. Allelic diversity of a population/deme -- strictly a function of allele frequencies in the gene pool; quantified as hardy-weinberg expected heterozygosity -- the higher the heterozygosity, the higher the allelic diversity. As number of alleles increases, the possible heterozygous conditions increases much more rapidly than the possible homozygous conditions, so track heterozygosity as a measure of the genetic diversity of the pool. 1 - all of the homozygous frequencies = frequency of heterozygous genotypes summed. If sample two alleles in a population at random and they are different, indicates heterozygosity. If sample two alleles and they are same, they are identical by descent. - the higher the heterozygosity the lower the probability of getting two alleles that are identical by descent at random.
