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.