Joint estimation of immigration and mating system parameters in gymnosperms using the EM algorithm.

An EM algorithm procedure is presented for the maximum-likelihood joint estimation of immigration and mating system parameters of mixed-mating system models for gymnosperms. In addition to accommodating multiallelic and multilocus data in mature populations and pollen pools, the EM estimates are insensitive to allelic frequency changes in foreign population and may approach closer to global maximum-likelihood estimates with each iteration, regardless of initial starting values. Estimates of rates of selfing (Ŝ), outcrossing (Ô), and immigration (Î) derived from the model are bounded strictly within the natural biological range (i.e., 0 ≤ Ô + Î ≤ 1; Ŝ + Ô + Î = 1).