DEMEtics (version 0.8.1)

Gst and Gst.est: Gst and Gst.est - Fixation Indices

Description

Functions that calculate the degree of genetic differentiation between populations when the mean heterozygosity within populations Hs, the total heterozygosity of the pooled populations Ht and the sample sizes are known. The Hs and Ht can be calculated by using the functions Hs and Ht that are included in this package.

Usage

Gst(Hs, Ht, values)
Gst.est(Hs, Ht, values)

Arguments

Hs

The mean heterozygosity within populations. This value can be calculated by using the function Hs that is included in this package.

Ht

The heterozygosity of the pooled populations. This value can be calculated by using the function Ht that is included in this package.

values

A vector that contains the number of individuals that were sampled from each population (i.e. the sample sizes).

Value

• The measure of genetic differentiation, Gst or Gst.est, is returned. As the arguments Hs and Ht are values that were calculated for a single locus, Gst and Gst.est-values are measures of genetic differentiation for that single locus.

Details

Gst or Gst.est values are calculated according to equation 3 in Jost 2008 (p. 4018). For Gst.est, Hs and Ht are substituted by Nei and Chesser's (1983) estimators, Hs.est and Ht.est, that reduce the bias of Gst as it is estimated from a small sample that intends to represent the whole population (see Jost, 2008, p. 4022).

References

Jost, L. 2008 Gst and its relatives do not measure differentiation. Molecular Ecology 17, 18, p. 4015--4026. Nei M. and Chesser R. 1983 Estimation of fixation indices and gene diversities. Annals of Human Genetics 47, p. 253--259

See Also

Hs, Ht, all.pops.Gst, all.pops.Gst.est, pair.pops.Gst pair.pops.Gst.est

Examples

Hs <- 0.42
Ht <- 0.65
sample.sizes <- c(20,30,50) # 3 Populations with different sample sizes

Gst(Hs,Ht,sample.sizes)

Gst.est(Hs,Ht,sample.sizes)