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Genetic diversity is the total amount of genetic variability within a species. It can be measured in several ways, including: observed heterozygosity, expected heterozygosity, the mean number of alleles per locus, the percentage of loci that are polymorphic, and estimated effective population size.
then there are + = observed copies of the A allele and + = of the B allele, out of 20 total chromosome copies. The frequency p of the A allele is p = 15/20 = 0.75, and the frequency q of the B allele is q = 5/20 = 0.25.
F ST is the script used to represent this index when using the formula: = In this equation, H T represents the expected heterozygosity of the total population and H S is the expected heterozygosity of a sub-populations. Both measures of heterozygosity are measured at one loci.
In a complementary approach, the heterozygosity could be used instead. The panmictic equivalent for Aa is 2 p • q • = 0.4658, which is higher than that in the sampled bulk (0.3588) [black label "8"]. The sampling has caused the heterozygosity to decrease by 0.1070, which differs trivially from the earlier estimate because of rounding errors.
Heterozygosity values of 51 worldwide human populations. [10] Sub-Saharan Africans have the highest values in the world. In population genetics, the concept of heterozygosity is commonly extended to refer to the population as a whole, i.e., the fraction of individuals in a population that are heterozygous for a particular locus. It can also ...
where n 11, n 12, n 22 are the observed numbers of the three genotypes, AA, Aa, and aa, respectively, and n 1 is the number of A alleles, where = +. An example Using one of the examples from Emigh (1980), [7] we can consider the case where n = 100, and p = 0.34. The possible observed heterozygotes and their exact significance level is given in ...
The measures F IS, F ST, and F IT are related to the amounts of heterozygosity at various levels of population structure. Together, they are called F-statistics, and are derived from F, the inbreeding coefficient. In a simple two-allele system with inbreeding, the genotypic frequencies are:
Genetic variation can be identified at many levels. Identifying genetic variation is possible from observations of phenotypic variation in either quantitative traits (traits that vary continuously and are coded for by many genes, e.g., leg length in dogs) or discrete traits (traits that fall into discrete categories and are coded for by one or a few genes, e.g., white, pink, or red petal color ...