Evidence for selection in response to radiation exposure: Pinus sylvestris in the Chernobyl exclusion zone.

Changes of genetic structures due to viability selection are likely to occur in populations exposed to rapidly and extremely changing environmental conditions after catastrophic events. However, very little is known about the extent of selective responses and in particular the proportion of the genome involved in putatively adaptive reactions for non-model plants. We used amplified fragment length polymorphisms (AFLPs) in order to investigate genetic differences between pine (Pinus sylvestris) trees which were partially exposed to extreme environmental conditions. Genetic variation patterns of pines exposed to high radiation in the Chernobyl exclusion zone with or without phenotypic stress symptoms were compared to control trees with a similar origin. Six percent of the investigated loci (15 of 222 loci) were identified as candidates for selective responses. Moderate differentiation was observed between groups of trees showing either weak or strong phenotypic responses to high radiation levels.