Premise of the study Large scale studies on the genetic diversity of forest trees are relevant for the inventory, conservation and management of genetic resources and provide an insight into the geographical origins of the species. This is an appropriate approach to use in Castanea sativa Mill., a tree of great economic importance and the only species from the genus Castanea distributed in Europe. The history of C. sativa was deduced from fossil pollen data, but the large scale genetic structure of this species needs to be elucidated. We evaluated the genetic diversity of C. sativa in order to define previously unclarified genetic relationship between the populations from Turkey and those from Greece and western Europe. The influence of natural events such as glaciations and human impact in terms of species distribution are discussed. Methods Wild chestnut trees (779) were sampled in 31 European sites. Six polymorphic microsatellites were used for the analysis. A set of measures of intra and interpopulation genetic statistics were calculated. The population structure was inferred by using a Bayesian approach. Key results The population structure showed a genetic divergence between the eastern (Greek and Turkish) and western (Italian and Spanish) populations. Two gene pools and a zone of gene introgression in Turkey were revealed. Conclusions The inferred population structure shows a strong geographical correspondence with the hypothesized glacial refugia and rules out the migration of the chestnut from Turkey and Greece to Italy. The homogeneous gene pool observed in Italy and Spain could have been originated from common refugia along with human-mediated colonization. Keywords: Castanea sativa Mill., colonization, forest dynamic, genetic diversity, microsatellite, phylogeography, population structure.
MICROSATELLITE MARKERS REVEAL A STRONG GEOGRAPHICAL STRUCTURE IN THE EUROPEAN POPULATIONS OF Castanea sativa: EVIDENCE FOR MULTIPLE GLACIAL REFUGIA
Claudia Mattioni;Paola Pollegioni;Marcello Cherubini;Fiorella Villani
2013
Abstract
Premise of the study Large scale studies on the genetic diversity of forest trees are relevant for the inventory, conservation and management of genetic resources and provide an insight into the geographical origins of the species. This is an appropriate approach to use in Castanea sativa Mill., a tree of great economic importance and the only species from the genus Castanea distributed in Europe. The history of C. sativa was deduced from fossil pollen data, but the large scale genetic structure of this species needs to be elucidated. We evaluated the genetic diversity of C. sativa in order to define previously unclarified genetic relationship between the populations from Turkey and those from Greece and western Europe. The influence of natural events such as glaciations and human impact in terms of species distribution are discussed. Methods Wild chestnut trees (779) were sampled in 31 European sites. Six polymorphic microsatellites were used for the analysis. A set of measures of intra and interpopulation genetic statistics were calculated. The population structure was inferred by using a Bayesian approach. Key results The population structure showed a genetic divergence between the eastern (Greek and Turkish) and western (Italian and Spanish) populations. Two gene pools and a zone of gene introgression in Turkey were revealed. Conclusions The inferred population structure shows a strong geographical correspondence with the hypothesized glacial refugia and rules out the migration of the chestnut from Turkey and Greece to Italy. The homogeneous gene pool observed in Italy and Spain could have been originated from common refugia along with human-mediated colonization. Keywords: Castanea sativa Mill., colonization, forest dynamic, genetic diversity, microsatellite, phylogeography, population structure.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
