| Description | The heterozygosity or genetic diversity associated with the know Cohort samples. A measure of genetic variation in a population.
For example:
If an individual carries the gene for black hair and the gene for blond hair, we would say that individual is heterozygous for hair color. Heterozygosity may also refer to the percentage of locations on a chromosome that are heterozygous in an individual.
Heterozygosity may also refer to the percentage of locations on a chromosome that are heterozygous in an individual. These locations are called loci (the singular form is locus) and may contain more than one gene. The concept of heterozygosity is frequently extended from an individual to a population in the study of population genetics.
Heterozygosity in a population is calculated as follows:
1) Let pi be the frequency p of the allele that has an index number of i for a given locus. The value of pi may therefore range from 0 to 1.
2) Calculate the predicted heterozygosity for a single locus. This is given by the equation 1 - Σpi^2. Since the sum of the terms pi^2 is less than 1, the heterozygosity is a value between 0 and 1. Heterozygosity may therefore be expressed as a percentage.
3) Interpret the significance for the predicted heterozygosity at a single locus. The equation the equation 1 - Σpi^2 shows that the maximum heterozygosity occurs when the alleles for that locus are equally common. For example, for two equally common alleles, the heterozygosity is 1 - Σpi^2 = 1 - (1/2)^2 - (1/2)^2 = 1/2.
4) Calculate the predicted heterozygosity for multiple loci. In this case, we wish to find the average of the sum of the squares of the allele frequencies and subtract it from 1. Thus, the heterozygosity for multiple loci is 1 - 1/mΣΣpi^2.
5) Evaluate the observed heterozygosity of a population for a single locus. We have Ho = Σxi/n where Ho is the observed heterozygosity, n is the population and xi is 0 if the alleles in the individual with index i are equal and 1 if they are different.
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Alelle Frequency Rt
