Joint stationary moments of a two-island diffusion model of population subdivision.

An expression for joint stationary moments of a diffusion approximation to a generalized Wright-Fisher model, corresponding to two finite populations of equal sizes, with migration and mutation, is derived. This gives a complete description of the stationary distribution of allele frequencies in the balance between migration, mutation and genetic drift. We derive the sampling formula in terms of the joint stationary moments, and we also prove that the diffusion process corresponding to this model of population division is not reversible.