Fagus sylvatica is a keystone species shaping the most important natural and quasi-natural ecosystems of the mountains in the Mediterranean area. This work has the aims to evaluate the genetic structure of beech in the southernmost distribution areas and map relevant sub-populations for conservation genetics. The methods used are based on landscape genetics. Landscape genetic maps were generated from 7 microsatellite loci using 37 sub-populations sampled in southern Italy and two control subpopulations from Norway and Sicily. Ecological sources of variation were also recorded and evaluated. Genetic disequilibrium increased from the sub-population to the whole population. The significant differentiation among sub-population for nuclear markers was consistent with the outcrossing breeding system. Two main clusters spatially distributed according to a contact zone migration model were inferred. Chloroplast haplotype richness decreased when moving northward and was independent of the sub-population sample size. Nuclear allelic richness was evenly distributed and correlated with both gene diversity (He) and sub-population size. Sub-populations bearing both a low heterozygote deficit and high chloroplast haplotype richness were mapped in multiple sites, were spatially marginal, and interpreted as being associated with -glacial niches.
Landscape genetics of Fagus sylvatica in one of its glacial refuge areas
FIGLIUOLO, Giovanni
2011-01-01
Abstract
Fagus sylvatica is a keystone species shaping the most important natural and quasi-natural ecosystems of the mountains in the Mediterranean area. This work has the aims to evaluate the genetic structure of beech in the southernmost distribution areas and map relevant sub-populations for conservation genetics. The methods used are based on landscape genetics. Landscape genetic maps were generated from 7 microsatellite loci using 37 sub-populations sampled in southern Italy and two control subpopulations from Norway and Sicily. Ecological sources of variation were also recorded and evaluated. Genetic disequilibrium increased from the sub-population to the whole population. The significant differentiation among sub-population for nuclear markers was consistent with the outcrossing breeding system. Two main clusters spatially distributed according to a contact zone migration model were inferred. Chloroplast haplotype richness decreased when moving northward and was independent of the sub-population sample size. Nuclear allelic richness was evenly distributed and correlated with both gene diversity (He) and sub-population size. Sub-populations bearing both a low heterozygote deficit and high chloroplast haplotype richness were mapped in multiple sites, were spatially marginal, and interpreted as being associated with -glacial niches.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.