Search results for "phylogeny"
showing 10 items of 1398 documents
Network dynamics of eukaryotic LTR retroelements beyond phylogenetic trees
2009
Abstract Background Sequencing projects have allowed diverse retroviruses and LTR retrotransposons from different eukaryotic organisms to be characterized. It is known that retroviruses and other retro-transcribing viruses evolve from LTR retrotransposons and that this whole system clusters into five families: Ty3/Gypsy, Retroviridae, Ty1/Copia, Bel/Pao and Caulimoviridae. Phylogenetic analyses usually show that these split into multiple distinct lineages but what is yet to be understood is how deep evolution occurred in this system. Results We combined phylogenetic and graph analyses to investigate the history of LTR retroelements both as a tree and as a network. We used 268 non-redundant …
Diversity Arrays Technology (DArT) for Pan-genomic Evolutionary Studies of Non-model Organisms
2007
BackgroundHigh-throughput tools for pan-genomic study, especially the DNA microarray platform, have sparked a remarkable increase in data production and enabled a shift in the scale at which biological investigation is possible. The use of microarrays to examine evolutionary relationships and processes, however, is predominantly restricted to model or near-model organisms.Methodology/principal findingsThis study explores the utility of Diversity Arrays Technology (DArT) in evolutionary studies of non-model organisms. DArT is a hybridization-based genotyping method that uses microarray technology to identify and type DNA polymorphism. Theoretically applicable to any organism (even one for wh…
Multiplex PCR for species discrimination of Sclerotiniaceae by novel laccase introns
2006
Common PCR-based targets for the identification of filamentous fungi and yeasts are the sequences of the internal transcribed spacer region (ITS1, 5.8S rDNA, ITS2). Within the Sclerotiniaceae the ITS-region is homogenous and the identification is almost impossible. Furthermore, the lack of IGS-data (intergenic spacer region) requires new specific marker genes for a rapid identification of phytopathogenic Sclerotiniaceae. We sequenced and analyzed new laccase2 (lcc2) genes from the phylogenetically related Sclerotinia sclerotiorum (Lib.) de Bary, Sclerotinia minor Jagger, and Monilinia fructigena Honey. Comparative analysis revealed remarkable differences in length and sequence compared to t…
pcaH, a molecular marker for estimating the diversity of the protocatechuate-degrading bacterial community in the soil environment
2007
Microorganisms degrading phenolic compounds play an important role in soil carbon cycling as well as in pesticide degradation. The pcaH gene encoding a key ring-cleaving enzyme of the -ketoadipate pathway was selected as a functional marker. Using a degenerate primer pair, pcaH fragments were cloned from two agricultural soils. Restriction fragment length polymorphism (RFLP) screening of 150 pcaH clones yielded 68 RFLP families. Comparison of 86 deduced amino acid sequences displayed 70% identity to known PcaH sequences. Phylogenetic analysis results in two major groups mainly related to PcaH sequences from Actinobacteria and Proteobacteria phyla. This confirms that the developed primer pai…
Analysis of population genetic structure and variability using RAPD markers in the endemic and endangered Limonium dufourii (Plumbaginaceae)
1998
Limonium dufourii (Plumbaginaceae) is a triploid species, with apomictic reproduction, endemic to the east mediterranean coast of Spain, where it is present in only six populations with a few individuals in most of them. L. dufourii is included in the Red List of Endangered Species by the IUCN. Genetic variation and population structure in this species has been studied using RAPDs. Twelve different primers provided 124 reliable bands of which 33 were polymorphic among the 165 individuals analysed. Those polymorphic bands were able to define 44 different patterns, of which all but six were present in only one population. Several methods for statistical evaluation have been used for intra- an…
Late Quaternary distributional stasis in the submediterranean mountain plant Anthyllis montana L. (Fabaceae) inferred from ITS sequences and amplifie…
2002
Anthyllis montana is a submediterranean, herbaceous plant of the southern and central European mountains. The internal transcribed spacer (ITS) regions of nuclear ribosomal DNA were sequenced from multiple accessions of the species and several closely related taxa. In addition, amplified fragment length polymorphism (AFLP) was analysed from 71 individuals of A. montana collected in 20 localities, mainly in the Pyrenees, Alps, Italian Peninsula and Balkans. Our ITS phylogeny showed a sequential branching pattern in A. montana, implying a western Mediterranean origin followed by an eastward migration. ITS clock calibrations suggest that speciation of A. montana took place at the Pliocene-Plei…
Molecular phylogeny of parabasalids with emphasis on the order Cristamonadida and its complex morphological evolution
2009
1055-7903 doi: DOI: 10.1016/j.ympev.2009.03.011; Parabasalia represents a complex assemblage of species, which recently received extensive reorganization. The newly created order Cristamonadida unites complex hypermastigids belonging to the Lophomonadida like the joeniids, the multinucleate polymonad Calonymphidae, and well-developed trichomonads in the Devescovinidae. All these protists exclusively occur in the guts of termites and related insects. In this study, small subunit rRNA and glyceraldehyde-3-phosphate dehydrogenase genes were identified without cultivation from 14 species in Cristamonadida including previously unstudied genera such as Joenina, Joenia, Joenoides, Macrotrichomonas…
Phylogenetics of Anthyllis (Leguminosae: Papilionoideae: Loteae): Partial incongruence between nuclear and plastid markers, a long branch problem and…
2010
Abstract Phylogenetic relationships in the genus Anthyllis (Leguminosae: Papilionoideae: Loteae) were investigated using data from the nuclear ribosomal internal transcribed spacer regions (ITS) and three plastid regions (psbA–trnH intergenic spacer, petB–petD region and rps16 intron). Bayesian and maximum parsimony (MP) analysis of a concatenated plastid dataset recovered well-resolved trees that are topologically similar, with many clades supported by unique indels. MP and Bayesian analyses of the ITS sequence data recovered trees that have several well-supported topological differences, both among analyses, and to trees inferred from the plastid data. The most substantial of these concer…
Plant speciation in continental island floras as exemplified byNigellain the Aegean Archipelago
2008
Continental shelf island systems, created by rising sea levels, provide a premier setting for studying the effects of geographical isolation on non-adaptive radiation and allopatric speciation brought about by genetic drift. The Aegean Archipelago forms a highly fragmented complex of mostly continental shelf islands that have become disconnected from each other and the mainland in relatively recent geological times (ca<5.2 Ma). These ecologically fairly homogenous islands thus provide a suitable biogeographic context for assessing the relative influences of past range fragmentation, colonization, gene flow and drift on taxon diversification. Indeed, recent molecular biogeographic studies…
The evolution of substrate differentiation inMinuartiaseriesLaricifoliae(Caryophyllaceae) in the European Alps: In situ origin or repeated colonizati…
2013
Premise of the study Substrate specialization is often considered an important factor in evolutionary diversification. A classic example of divergence related to different substrate types is the dichotomy between calcicole and calcifuge plants on calcareous and siliceous substrates as found in the European Alps. When closely related species with contrasting substrate preferences are found in the same area, it is generally hypothesized that they diverged where they now occur. However, it is possible that Alpine edaphic diversity instead allows the coexistence of related species whose edaphic differentiation took place deeper in the phylogeny, in some other part of the range of their clades. …