Search results for "DISTANCE"
showing 10 items of 1009 documents
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…
Isolation by distance and sharp discontinuities in gene frequencies: implications for the phylogeography of an alpine insect species, Carabus solieri
2004
Analysis of genetic isolation by distance (IBD) is of prime importance for the study of processes responsible for spatial population genetic structure and is thus frequently used in case studies. However, the identification of a significant IBD pattern does not necessarily imply the absence of sharp discontinuities in gene frequencies. Therefore, identifying barriers to gene flow and/or secondary contact between differentiated entities remains a major challenge in population biology. Geographical genetic structure of 41 populations (1080 individuals) of an alpine insect species, Carabus solieri , was studied using 10 microsatellite loci. All populations were significantly differentiated and…
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…
The Role of Ancestral Duplicated Genes in Adaptation to Growth on Lactate, a Non-Fermentable Carbon Source for the Yeast Saccharomyces cerevisiae
2021
This article belongs to the Section Molecular Informatics.
Estimation of Purkinje trees from electro-anatomical mapping of the left ventricle using minimal cost geodesics
2015
The electrical activation of the heart is a complex physiological process that is essential for the understanding of several cardiac dysfunctions, such as ventricular tachycardia (VT). Nowadays, patient-specific activation times on ventricular chambers can be estimated from electro-anatomical maps, providing crucial information to clinicians for guiding cardiac radio-frequency ablation treatment. However, some relevant electrical pathways such as those of the Purkinje system are very difficult to interpret from these maps due to sparsity of data and the limited spatial resolution of the system. We present here a novel method to estimate these fast electrical pathways from the local activati…
How the AIS can Improve its Contributions to the UN’s Sustainability Development Goals: Towards A Framework for Scaling Collaborations and Evaluating…
2021
In March, 2020, the coronavirus disease of 2019 (COVID-19) pandemic affected the information systems (IS) higher education community (along with the rest of the world) profoundly. Higher education institutes across the world had to quickly shift to online courses. In some cases, faculty had to transition their courses in only days. In response, the Communications of the Association for Information Systems launched a special issue on COVID-19, learning, pedagogy, and educational systems to provide a forum for IS faculty around the world to share effective practices and opinions regarding the long-term consequences of the COVID-19 pandemic on IS education. This paper serves as the editorial f…