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Mitochondrial COI (mitochondrial + coi)
Selected AbstractsIncipient speciation of Catostylus mosaicus (Scyphozoa, Rhizostomeae, Catostylidae), comparative phylogeography and biogeography in south-east AustraliaJOURNAL OF BIOGEOGRAPHY, Issue 3 2005Michael N Dawson Abstract Aim, Phylogeography provides a framework to explain and integrate patterns of marine biodiversity at infra- and supra-specific levels. As originally expounded, the phylogeographic hypotheses are generalities that have limited discriminatory power; the goal of this study is to generate and test specific instances of the hypotheses, thereby better elucidating both local patterns of evolution and the conditions under which the generalities do or do not apply. Location, Coastal south-east Australia (New South Wales, Tasmania and Victoria), and south-west North America (California and Baja California). Methods, Phylogeographic hypotheses specific to coastal south-east Australia were generated a priori, principally from existing detailed distributional analyses of echinoderms and decapods. The hypotheses are tested using mitochondrial cytochrome c oxidase subunit I (COI) and nuclear internal transcribed spacer 1 (ITS1) DNA sequence data describing population variation in the jellyfish Catostylus mosaicus, integrated with comparable data from the literature. Results, Mitochondrial COI distinguished two reciprocally monophyletic clades of C. mosaicus (mean ± SD: 3.61 ± 0.40% pairwise sequence divergence) that were also differentiated by ITS1 haplotype frequency differences; the boundary between the clades was geographically proximate to a provincial zoogeographic boundary in the vicinity of Bass Strait. There was also limited evidence of another genetic inhomogeneity, of considerably smaller magnitude, in close proximity to a second hypothesized zoogeographic discontinuity near Sydney. Other coastal marine species also show genetic divergences in the vicinity of Bass Strait, although they are not closely concordant with each other or with reported biogeographic discontinuities in the region, being up to several hundreds of kilometres apart. None of the species studied to date show a strong phylogeographic discontinuity across the biogeographic transition zone near Sydney. Main conclusions, Patterns of evolution in the Bass Strait and coastal New South Wales regions differ fundamentally because of long-term differences in extrinsic factors. Since the late Pliocene, periods of cold climate and low sea-level segregated warm temperate organisms east or west of an emergent Bassian Isthmus resulting in population divergence and speciation; during subsequent periods of warmer and higher seas, sister taxa expanded into the Bass Strait region leading to weakly correlated phylogeographic and biogeographic patterns. The Sydney region, by contrast, has been more consistently favourable to shifts in species' ranges and long-distance movement, resulting in a lack of intra-specific and species-level diversification. Comparisons between the Sydney and Bass Strait regions and prior studies in North America suggest that vicariance plays a key role in generating coastal biodiversity and that dispersal explains many of the deviations from the phylogeographic hypotheses. [source] Systematic position of the pelagic Thecosomata and Gymnosomata within Opisthobranchia (Mollusca, Gastropoda) , revival of the PteropodaJOURNAL OF ZOOLOGICAL SYSTEMATICS AND EVOLUTIONARY RESEARCH, Issue 2 2006A. Klussmann-Kolb Abstract The complete 18S (SSU) rRNA as well partial 28S (LSU) rRNA and partial mitochondrial COI sequences have been used to reconstruct the phylogenetic relationships within Opisthobranchia with special focus on the pelagic orders Thecosomata and Gymnosomata. Maximum parsimony, maximum likelihood, distance as well as Bayesian analysis of a combined dataset of the three genes reveals that Thecosomata and Gymnosomata are sister groups and together are closely related to Anaspidea. Possible sister taxon to Thecosomata, Gymnosomata and Anaspidea is Cephalaspidea s. str. Analysis of a taxon-extended dataset of partial 28S sequences supported a basal position of Limacina within Euthecosomata. Within Cavolinidae, Creseis is basal to the other taxa. Other phylogenetic implications from the present results are also discussed. Investigation of the morphology and histology of Thecosomata and Gymnosomata as well as several other opisthobranch taxa helped to identify autapomorphies for Thecosomata and Gymnosomata as well as apomorphies for the clades including these taxa. Zusammenfassung Auf Basis der kompletten 18S rRNA- und partiellen 28S rRNA- sowie partiellen COI- Sequenzen wurde die Phylogenie der Opisthobranchia unter besonderer Berücksichtigung der pelagischen Thecosomata und Gymnosomata rekonstruiert. Maximum Parsimonie-, Maximum Likelihood- sowie Distanz- Berechnungen und Bayes'sche Analysen zeigen, dass die Thecosomata und Gymnosomata Schwestergruppen und nah verwandt mit den Anaspidea sind. Die potentielle Schwestergruppe zu Thecosomata, Gymnosomata und Anaspidea sind die Cephalaspidea s. str. Die Analyse eines taxonerweiterten Datensatzes von partiellen 28S rRNA-Sequenzen unterstützt die basale Position von Limacina innerhalb der Euthecosomata. Innerhalb der Cavolinidae stellt Creseis das basalste Taxon dar. Weitere Schlussfolgerungen zu phylogenetischen Verwandtschaftsverhältnissen der Opisthobranchia auf Grundlage der vorliegenden Untersuchungen werden diskutiert. Die Untersuchungen der Morphologie und Histologie der Thecosomata und Gymnosomata sowie anderer Opisthobranchia ließen apomorphe Merkmale der Thecosomata und Gymnosomata sowie Apomorphien der Kladen, die diese beiden pelagischen Taxa enthalten, erkennen. [source] The colonization of Europe by the freshwater crustacean Asellus aquaticus (Crustacea: Isopoda) proceeded from ancient refugia and was directed by habitat connectivityMOLECULAR ECOLOGY, Issue 14 2005R. VEROVNIK Abstract Recent continental-scale phylogeographic studies have demonstrated that not all freshwater fauna colonized Europe from the classic Mediterranean peninsular refugia, and that northern or central parts of the continent were occupied before, and remained inhabited throughout the Pleistocene. The colonization history of the ubiquitous aquatic isopod crustacean Asellus aquaticus was assessed using mitochondrial COI and a variable part of nuclear 28S rDNA sequences. Phylogeographic analysis of the former suggested that dispersion proceeded possibly during late Miocene from the western part of the Pannonian basin. Several areas colonized from here have served as secondary refugia and/or origins of dispersion, well before the beginning of the Pleistocene. Postglacial large-scale range expansion was coupled with numerous separate local dispersions from different refugial areas. Connectivity of the freshwater habitat has played an important role in shaping the current distribution of genetic diversity, which was highest in large rivers. The importance of hydrographic connections for the maintenance of genetic contact was underscored by a discordant pattern of mtDNA and nuclear rDNA differentiation. Individuals from all over Europe, differing in their mtDNA to a level normally found between species or even genera (maximal within population nucleotide divergence reached 0.16 ± 0.018), shared the same 28S rRNA gene sequence. Only populations from hydrographically isolated karst water systems in the northwestern Dinaric Karst had distinct 28S sequences. Here isolation seemed to be strong enough to prevent homogenization of the rRNA gene family, whereas across the rest of Europe genetic contact was sufficient for concerted evolution to act. [source] Deeply divergent mitochondrial lineages reveal patterns of local endemism in chironomids of the Australian Wet TropicsAUSTRAL ECOLOGY, Issue 3 2009MATT N. KROSCH Abstract The Wet Tropics bioregion of north-eastern Australia has been subject to extensive fluctuations in climate throughout the late Pliocene and Pleistocene. Cycles of rainforest contraction and expansion of dry sclerophyll forest associated with such climatic fluctuations are postulated to have played a major role in driving geographical endemism in terrestrial rainforest taxa. Consequences for the distributions of aquatic organisms, however, are poorly understood. The Australian non-biting midge species Echinocladius martini Cranston (Diptera: Chironomidae), although restricted to cool, well-forested freshwater streams, has been considered to be able to disperse among populations located in isolated rainforest pockets during periods of sclerophyllous forest expansion, potentially limiting the effect of climatic fluctuations on patterns of endemism. In this study, mitochondrial COI and 16S data were analysed for E. martini collected from eight sites spanning the Wet Tropics bioregion to assess the scale and extent of phylogeographic structure. Analyses of genetic structure showed several highly divergent cryptic lineages with restricted geographical distributions. Within one of the identified lineages, strong genetic structure implied that dispersal among proximate (<1 km apart) streams was extremely restricted. The results suggest that vicariant processes, most likely due to the systemic drying of the Australian continent during the Plio-Pleistocene, might have fragmented historical E. martini populations and, hence, promoted divergence in allopatry. [source] | ||||||||||