Four-gamete test (source code)

= Four-gamete test
{wiki}

Under an <infinite sites mutation model>, two variable sites on one unrecombined rooted tree have nested or disjoint derived-allele clades. At most three of the four biallelic <haplotypes> can then occur. Observation of all four haplotypes proves that the single-tree, single-mutation-per-site model cannot hold: some ancestral <genetic recombination> is necessary if recurrent mutation is excluded. The test gives no proof of absence of recombination when only three haplotypes occur.

// Target: biology.bigb