# heterozygosity

##### Heterozygosity at a Locus Using Gene Frequencies

This function computes the mean heterozygosity from gene frequencies, and returns optionally the associated variance.

##### Usage

```
heterozygosity(x, variance = FALSE)
H(x, variance = FALSE)
```

##### Arguments

- x
- a vector or a factor.
- variance
- a logical indicating whether the variance of the
estimated heterozygosity should be returned (
`TRUE`

), the default being`FALSE`

.

##### 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 mean heterozygosity is estimated with:

$$\hat{H} = \frac{n}{n-1} \left(1 - \sum_{i=1}^k p_i^2 \right)$$

where $n$ is the number of genes in the sample, $k$ is the number of alleles, and $p_i$ is the observed (relative) frequency of the allele $i$.

##### Value

- a numeric vector of length one with the estimated mean heterozygosity
(the default), or of length two if the variance is returned
`variance = TRUE`

.

##### References

Nei, M. (1987) *Molecular evolutionary genetics*. New York:
Columbia University Press.

##### See Also

*Documentation reproduced from package ape, version 2.1-1, License: GPL (>= 2)*