Science and Technology Production
The effect of volcanism on postglacial migration and seed dispersal. A case study in southern South America
Article
Date:
2008Publishing House and Editing Place:
Springer VerlagMagazine:
Tree Genetics and Genomes, vol. 4 (pp. 435-443) - ISSN 1614-2942Springer Verlag
ISSN:
1614-2942Summary *
Abstract During the Quaternary, southern South American temperate forests were confined to small and isolated refugia. Recolonization could be related not only with location of refugia but also with postglacial phenomena like volcanism, which could have interrupted the expansion of the forests. The aim of this study was to analyze the local effect of volcanism during the postglacial migration of Nothofagus nervosa in a particular region of Argentina were convergence of two migratory routes was suggested. The main question is whether admixture occurred or not and if the current populations are connected by pollen or seed gene flow. Two populations separated by a 3-kmwidth lava flow were sampled. Buds from 30 individuals of each of the two populations and from a total of 142 juveniles were analyzed. Genetic variation was detected through maternally inherited chloroplast deoxyribonucleic acid (cpDNA; polymerase chain reaction restriction fragment length polymorphisms of two fragments) and nuclear markers like isozymes (six loci) and simple sequence repeats (three loci). Population genetic parameters were estimated and the existence of a genetic structure was tested with an analysis of molecular variance. Historical gene flow was estimated through the indirect method of the genetic differentiation (FST). Chloroplast DNA revealed a total genetic differentiation between the two populations indicating completely isolation respecting seed gene flow. On the contrary, the degree of genetic differentiation for the nuclear markers was significantly lower, and moderate levels of historical gene flow through pollen were inferred. The results suggest that in this area, volcanism has played an important local role during the expansion of N. nervosa maintaining these two populations separated. Publicado on line: enero 2008 DOI 10.1007/s11295-007-0121-1 Information provided by the agent in SIGEVAKey Words
GLACIAL HISTORYSSRSCPDNAGENE FLOW