Based on two polymorphic chloroplast microsatellites that had been previously identified and sequence characterized in the genus Abies, genetic variation was studied in a total of 714 individuals from 17 European silver fir (Abies alba Mill.) populations distributed all over the natural range. We found eight and 18 different length variants at each locus, respectively, which combined into 90 different haplotypes. Genetic distances between most populations were high and significant. There is also evidence for spatial organization of the distribution of haplotypes, as shown by permutation tests, which demonstrate that genetic distances increase with spatial distances. A large heterogeneity in levels of diversity across populations was observed. Furthermore, there is good congruence in the levels of allelic richness of the two loci across populations. The present organization of levels of allelic richness across the range of the species is likely to have been shaped by the distribution of refugia during the last glaciation and the subsequent recolonization processes.

No abstract

Three chloroplast microsatellites (cpSSRs), previously sequence characterized and for which paternal inheritance was tested and confirmed, were used to assess their usefulness as informative markers for phylogeographic studies in Norway spruce (Picea abies K.) and to detect spatial genetic differentiation related to the possible recolonization processes in the postglacial period. Ninety-seven populations were included in the survey. Some 8, 7, and 6 different size variants for the three cpSSRs, respectively, were scored by analysing 1105 individuals. The above 21 variants combined into 41 different haplotypes. The distribution of some haplotypes showed a clear geographic structure and seems to be related to the existence of different refugia during the last glacial period. The analysis of chloroplast SSR variation detected the presence of two main gene pools (Sarmathic-Baltic and Alpine--Centre European) and a relatively low degree of differentiation (RST of about 10%), characteristic of tree species with large distribution and probably influenced by an intensive human impact on this species. Based on our data, we were not able to detect any evidence concerning the existence of additional gene pools (e.g., from Balkan and Carpathian glacial refugia), though we cannot exclude the existence of genetic discontinuity within the species' European range. A large proportion of population-specific haplotypes were scored in this species, thus indicating a possible usefulness of these markers for the identification of provenances, seed-lots, and autochthonous stands.

In this investigation, nine chloroplast, paternally inherited simple‐sequence repeat (cpSSR) markers were used to describe genetic variation of three closely related species belonging to the halepensis complex (Pinus halepensis Ait., P. brutia Mill. and P. eldarica Medwed.). Both the infinite allele model (IAM) and stepwise‐mutation model (SMM) have been applied to the analysis of the genetic structure of natural populations and the geographical distribution of haplotypic variation. SMM‐based estimators performed better than IAM‐based estimators for large values of within‐population diversity and divergence between population pairs. Overall, large haplotypic variation and high genetic divergence were detected for both P. halepensis and P. brutia. The genetic structures of the three species are discussed with consideration to the evolutionary and ecological characteristics of these species. Three highly informative markers showing size variants distinguishing P. halepensis from the other two species were used to provide more information on the occurrence of natural hybridization in a Turkish sympatric population of P. halepensis and P. brutia. Strong evidence of introgression of ‘halepensis’ chloroplast haplotypes into P. brutia seeds (but not vice versa) was detected. According to previous evidence from controlled crossings, matings between the above species seem to be successful only when P. halepensis is the pollen donor and P. brutia is the female parent (but not reciprocally). The existence of unidirectional gene flow in sympatric populations confirms previous evidence about partial reproductive barriers between P. halepensis and P. brutia. Implications of the above evidence for the evolutionary history of these species are discussed.

No abstract

We studied the phylogenetic relationships among the three stone pine species, Pinus cembra, P. sibirica, and P. pumila, using chloroplast microsatellites and mitochondrial nad1 intron 2 sequences. The three chloroplast microsatellite loci combined into a total of 18 haplotypes. Fourteen haplotypes were detected in 15 populations of P. cembra and one population of P. sibirica, five of which were shared between the two species, and the two populations of P. pumila comprised four species-specific haplotypes. Mitochondrial intron sequences confirmed this grouping of species. Sequences of P. cembra and P. sibirica were identical, but P. pumila differed by several nucleotide substitutions and insertions/deletions. A repeat region found in the former two species showed no intraspecific variation. These results indicate a relatively recent evolutionary separation of P. cembra and P. sibirica, despite their currently disjunct distributions. The species-specific chloroplast and mitochondrial markers of P. sibirica and P. pumila should help to trace the hybridization in their overlapping distribution area and to identify fossil remains with respect to the still unresolved postglacial re-colonization history of these two species.

This study describes the application of previously characterized chloroplast microsatellites as markers for paternity analysis in a conifer species. The investigations were performed on silver fir (Abies alba Mill.) relic trees in an endangered population of the Ore Mountains (Germany). Two relatively isolated adult trees about 30 m apart, as well as 24 naturally regenerated young trees in their direct neighborhood, were analyzed at two chloroplast microsatellite loci. Results reveal the potential usefulness of the markers for paternity analysis.

Three chloroplast microsatellites (cpSSRs), previously sequence characterized and for which paternal inheritance was tested and confirmed, were used to assess their usefulness as informative markers for phylogeographic studies in Norway spruce (Picea abies K.) and to detect spatial genetic differentiation related to the possible recolonization processes in the postglacial period. Ninety-seven populations were included in the survey. Some 8, 7, and 6 different size variants for the three cpSSRs, respectively, were scored by analysing 1105 individuals. The above 21 variants combined into 41 different haplotypes. The distribution of some haplotypes showed a clear geographic structure and seems to be related to the existence of different refugia during the last glacial period. The analysis of chloroplast SSR variation detected the presence of two main gene pools (Sarmathic-Baltic and Alpine--Centre European) and a relatively low degree of differentiation (RST of about 10%), characteristic of tree species with large distribution and probably influenced by an intensive human impact on this species. Based on our data, we were not able to detect any evidence concerning the existence of additional gene pools (e.g., from Balkan and Carpathian glacial refugia), though we cannot exclude the existence of genetic discontinuity within the species' European range. A large proportion of population-specific haplotypes were scored in this species, thus indicating a possible usefulness of these markers for the identification of provenances, seed-lots, and autochthonous stands.