ESTIMATING PLANT DISPERSAL FROM PARENTAGE ANALYSIS DATA THROUGH AN E-M ALGORITHM Nikolaos Nanos, UD Anatomia, ETSI Montes, Universidad Politécnica de Madrid Seed dispersal in plant populations is a process that links the end of the life cycle of adult plants with the establishment of their offspring. The dispersal distance (i.e. the distance separating offspring from their parent-trees) is an interesting measure of population spread in a variety of scientific disciplines such as genetics, forestry or ecology. Frequently we employ genetical markers in order to study seed dispersal and assign parents to genotyped offspring. The problem when using these markers is that we can not distinguish the seed source plant from the pollen donor. Furthermore, parents of genotyped offspring may not be detected among those analyzed (due to incoming gene flow). In this seminar I will present a stochastic EM algorithm for calculating the missing part of the data, aiming at the estimation of both the mother-to-offspring and the father-to-offspring distributions of dispersal distances. The method relies heavily on the assumption of two parametric models (probability densities) governing seed and pollen dispersal. This work has been recently submitted and rejected by a peer-reviewed journal. After presenting the general statistical framework of this work, I will discuss the referee’s comments.