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In population genetics, F-statistics (also known as fixation indices) describe the statistically expected level of heterozygosity in a population; more specifically the expected degree of (usually) a reduction in heterozygosity when compared to Hardy–Weinberg expectation.
Fst values between European populations. The fixation index (F ST) is a measure of population differentiation due to genetic structure.It is frequently estimated from genetic polymorphism data, such as single-nucleotide polymorphisms (SNP) or microsatellites.
Tajima's D is a population genetic test statistic created by and named after the Japanese researcher Fumio Tajima. [1] Tajima's D is computed as the difference between two measures of genetic diversity: the mean number of pairwise differences and the number of segregating sites, each scaled so that they are expected to be the same in a neutrally evolving population of constant size.
In population genetics, the Wahlund effect is a reduction of heterozygosity (that is when an organism has two different alleles at a locus) in a population caused by subpopulation structure. Namely, if two or more subpopulations are in a Hardy–Weinberg equilibrium but have different allele frequencies , the overall heterozygosity is reduced ...
The proportion of segregating sites within a gene is an important statistic in population genetics since it can be used to estimate mutation rate assuming no selection. For example it is used to calculate the Tajima's D neutral evolution statistic. A sequence alignment, produced by ClustalO, of mammalian histone proteins.
Genetic diversity is a measure of the number of different alleles or combinations of alleles present in a population. This may be measured by the amount of heterozygosity measured compared to the expected amount of heterozygosity predicted by Hardy-Weinberg Equilibrium. Evaluating genetic diversity in the genomes of populations can inform us ...
The pregnancy outcome is strongly chromosome specific. The most frequently seen trisomic cells in confined placental mosaicism involve chromosomes 2, 3, 7, 8 and 16. The next frequently involved are 9, 13, 15, 18, 20 and 22. [8] It has been observed that CPM involving the sex chromosomes usually has no adverse effects on fetal development. [9]
Population structure (also called genetic structure and population stratification) is the presence of a systematic difference in allele frequencies between subpopulations. In a randomly mating (or panmictic) population, allele frequencies are expected to be roughly similar between groups. However, mating tends to be non-random to some degree ...