pegas (version 1.3)

theta.h: Population Parameter THETA using Homozygosity

Description

This function computes the population parameter THETA using the homozygosity (or mean heterozygosity) from gene frequencies.

Usage

theta.h(x, standard.error = FALSE)

Value

A numeric vector of length one with the estimated theta (the default), or of length two if the standard error is returned (standard.error = TRUE).

Arguments

x

a vector or a factor.

standard.error

a logical indicating whether the standard error of the estimated theta should be returned (TRUE), the default being FALSE.

Author

Emmanuel Paradis

Details

The argument x can be either a factor or a vector. If it is a factor, then it is taken to give the individual alleles in the population. If it is a numeric vector, then its values are taken to be the numbers of each allele in the population. If it is a non-numeric vector, it is a coerced as a factor.

The standard error is computed with an approximation due to Chakraborty and Weiss (1991).

References

Zouros, E. (1979) Mutation rates, population sizes and amounts of electrophoretic variation at enzyme loci in natural populations. Genetics, 92, 623--646.

Chakraborty, R. and Weiss, K. M. (1991) Genetic variation of the mitochondrial DNA genome in American Indians is at mutation-drift equilibrium. American Journal of Physical Anthropology, 86, 497--506.

See Also

heterozygosity, theta.s, theta.k, theta.tree

Examples

data(jaguar)
## compute frequencies:
S <- summary(jaguar)
## compute THETA for all loci:
sapply(S, function(x) theta.h(x$allele))