Genetic variation and migration pathways of maritime pine (Pinus pinaster Ait) in the Iberian peninsula

The genetic variability and migration pathways of Pinus pinaster after glac iation in the Iberian peninsula was studied by means of 18 loci from 12 nat ural populations of the species. The analysis showed the existence of three groups of populations with different levels of diversity and patterns of r ecolonization. The southern Iberian group displays a high level of diversit y, with a stepping-stone model of variation. The presence of rare alleles i n this group and their position in the phylogenetic tree suggest the existe nce of refugia during glaciations in this zone. The eastern Iberian group a lso has high levels of diversity but is clearly separate from the first gro up based on their genetic distances. The Atlantic group displays a low leve l of diversity that could be interpreted as a rapid recolonization of the e ntire area by the Eastern group that has not yet developed to a divergence in this area. The southern Iberian range is indicated to be the dispersal c entre of the species after the last glaciation.