Assortative mating Mating patterns where individuals do not mate in proportion to their genotype frequencies in the population; mating that is more (positive assortative mating) or less (negative assortative mating) frequent with respect to genotype or genetically based phenotype frequency than expected by random combination. Consanguineous mating Mating between related individuals that can take the form using the genotype counting method to estimate allele frequency (Table 2.8 uses the allele counting method). The frequency of the b allele, q, can be estimated directly in a similar fashion or by subtraction (q = 1 - p = 1 -0.78 = 0.22) since there are only two alleles in this case. The Hardy-Weinberg expected frequency of heterozygotes is He = 2pq = 2(0.78)(0.22) = 0.343. It is then simple to estimate the fixation index using the observed and expected heterozygosities:

Table 2.8

Observed genotype counts and frequencies in a sam

ple of N = 200 individuals for a single locus

with two alleles. Allele frequencies in

the population can be estimated from the genotype frequencies by

summing the total count of each allele and dividing it by the total number of alleles in the sample (2N).



Observed frequency

Allele count

Allele frequency

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