Search results for "genetic distance"
showing 10 items of 62 documents
Genetic diversity in Sicilian populations of Quercus ilex (Fagaceae)
2013
Raimondo, F. M., Scialabba, A., Guarino, R. & Spallino, R. E.: Genetic diversity in Sicilian populations of Quercus ilex (Fagaceae). — Fl. Medit. 23: 245-253. 2013. — ISSN: 1120-4052 printed, 2240-4538 online. Recent studies on the genetic structure of the Italian populations of Quercus ilex demonstrated their high diversity, particularly in the Sicilian metapopulation. In order to check if the holm oak stands in the mountains of NW Sicily could have some relationship with Q. ilex subsp. ballota (distributed in Spain and NW Africa), 26 specimens from the Sicilian most distinctive Q. ilex populations have been compared with some representative populations of the Italian Peninsula, North Afri…
Long‐distance dispersal vs vicariance: the origin and genetic diversity of alpine plants in the Spanish Sierra Nevada
2006
Here, we investigated the origin and genetic diversity of four alpine plant species co-occurring in the Spanish Sierra Nevada and other high mountains in south-western Europe by analysis of amplified fragment length polymorphisms (AFLPs). In Kernera saxatilis, Silene rupestris and Gentiana alpina we found intraspecific phylogroups corresponding to mountain regions as predicted by the vicariance hypothesis. Moreover, genetic distances between Sierra Nevada and Pyrenees populations were always higher than those between populations from the Pyrenees and the south-western Alps/Massif Central. This suggests successive disruption of gene exchange between mountain ranges as postglacial climatic wa…
Are and bivoltine (Lepidoptera: Lycaenidae)? The discriminatory value of genetics in taxonomy
2005
Abstract Taxonomic confusion exists in several sibling species groups. The Polyommatus coridon species complex (Chalk Hill Blues) serves as a model group of sibling species in which genetic analyses provide suitable means for taxonomic clarification. We studied the allozyme patterns of the two described bivoltine species of this complex, Polyommatus hispana and Polyommatus slovacus , and compared them to the two genetic lineages of the univoltine P. coridon. P. hispana is well distinguished from P. coridon (genetic distance: 0.081), and most probably is a sibling species that has evolved during glacial isolation on the Iberian Peninsula. P. slovacus is genetically indistinguishable from the…
RAPD variation within and among natural populations of outcrossing willow-leaved foxglove (Digitalis obscura L.)
1999
Random amplified polymorphic DNA (RAPD) markers were used to assess levels and patterns of genetic diversity in Digitalis obscura L. (Scrophulariaceae), an outcrossing cardenolide-producing medicinal plant species. A total of 50 plants from six natural populations on the Iberian Peninsula were analysed by six arbitrarily chosen decamer primers resulting in 96 highly reproducible RAPD bands. To avoid bias in parameter estimation, analyses of population genetic structure were restricted to bands (35 of 96) whose observed frequencies were less than 1–3/n in each population. The analysis of molecular variance (AMOVA) with distances among individuals corrected for the dominant nature of RAPDs (g…
Complete genome of a European hepatitis C virus subtype 1g isolate: phylogenetic and genetic analyses
2008
Abstract Background Hepatitis C virus isolates have been classified into six main genotypes and a variable number of subtypes within each genotype, mainly based on phylogenetic analysis. Analyses of the genetic relationship among genotypes and subtypes are more reliable when complete genome sequences (or at least the full coding region) are used; however, so far 31 of 80 confirmed or proposed subtypes have at least one complete genome available. Of these, 20 correspond to confirmed subtypes of epidemic interest. Results We present and analyse the first complete genome sequence of a HCV subtype 1g isolate. Phylogenetic and genetic distance analyses reveal that HCV-1g is the most divergent su…
An assessment of genetic relationships within the genus Digitalis based on PCR-generated RAPD markers
2000
RAPD markers were used to study inter-specific variation among six species of the genus Digitalis: D. obscura, D. lanata, D. grandiflora, D. purpurea, D. thapsi and D. dubia, and the hybrid D. excelsior (D. purpurea×D. grandiflora). A total of 91 highly reproducible bands amplified with four arbitrarily chosen decamer primers were obtained. Homology of the co-emigrating RAPD markers was tested by blot hybridisation and sequencing of selected bands. The application of a range of statistical approaches for RAPD data analysis, including distance and parsimony methods, family clustering and the analysis of molecular variance (AMOVA), indicated that these molecular markers were taxonomically inf…
A hierarchical analysis of genetic structure and variability in patchily distributed coexisting Chiastocheta species (Diptera:Anthomyiidae)
1996
The pattern of genetic variation in four coexisting fly species of the genus Chiastocheta was studied by allozyme electrophoresis. The fly species are confined to patches of one plant, Trollius europaeus, and thus experience very similar habitat fluctuations. Collection sites were chosen in a hierarchical fashion and F-statistics were estimated at three levels: intraregion, inter-region and total population. Population characteristic genetic parameters were compared within and among species and were related to the hierarchical level. The species were used as replicate experiments for inference of habitat history, and the hierarchical levels were used as inference for specific gene flow patt…
Evaluation of morphological and genetic diversity of loquat accessions grown in sicily
2015
In this study 20 accessions of loquat (Eriobotrya japonica Lindl.) that originated from Sicily and other countries were characterized phenotypically and genotyped using seven microsatellite markers. The microsatellites clearly distinguished 14 accessions; three pairs of local accessions were not differentiated, and three accessions from abroad can be considered bud sport mutations of the main Spanish cultivar âAlgerieâ. The mean alleles per locus was four, ranging from two with the marker EJ075 and five with EJ012 and EJ271; the mean Polymorphic Information Content was 0.53; the average expected and observed heterozygosities resulted 0.62 and 0.59, respectively. These values revealed a …
Genetic variation of an Italian long shelf-life tomato (Solanum lycopersicon L.) collection by using SSR and morphological fruit traits
2014
The recovery of ancient germplasm in tomato (Solanum lycopersicon L.) has become necessary to limit the wide genetic erosion caused by the employment of modern cultivars. Among germplasm collections, long shelf-life landraces could represent an important source of biodiversity. The present study provides a first set of molecular and phenotypic data on long shelf-life (so called "da serbo" in southern Italy) tomato collection, mainly originated from Sicily together with some landraces from Campania and Apulia. The analysis of fruit traits showed a low intra-varietal variation, while exhibiting a quite higher inter-varietal variability. Overall, the cultivars have been classified in six fruit…
Organ xenografting between rodents: an evolutionary perspective
1994
Rejection times of heart xenografts in several donor-recipient combinations including the guinea pig, rat, hamster, and mouse are examined in light of the paleontological history of rodents and the resulting phylogenetic distances between taxa. This multidisciplinary review at the molecular, chromosomal and morphological levels suggests that xenograft rejection time is inversely proportional to the time divergence or phylogenetic distance, and that the binomial terminology concordant/discordant does not reflect the amplitude of phylogenetic distances.