Fst

F_st is a measure of population divergence. It measures the reduction in heterozygosity in a subdivided population compared to that in large, random mating population with the same allele frequencies.

Formulae

For the simple case of two populations, this is simply:

$F_{st}=(p_1-p_2{)}^2/2\bar{p}(1-\bar{p})$

Where:

$\bar{p}=(p_1+p_2)/2$

References

Nielsen R, Mountain JL, Huelsenbeck JP and Slatkin M (1998) Maximum-Likelihood Estimation of Population Divergence Times and Population Phylogeny in Models Without Mutation. Evolution 52:669-677

Reynolds J, Weir BS and Cockerham CC (1983) Estimation of the coancestry coefficient: basis for a short-term genetic distance. Genetics 105:767-779.