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Figure 6 in Talitrid amphipods (Crustacea: Amphipoda: Talitridae) and the driftwood ecological niche: a morphological and molecular study
No full textFigure 6. Scattergram and fitted linear regressions as in Figure 4. A2 FA, second antenna flagellum article count.Published as part of Wildish, D.J., Pavesi, L. & Ketmaier, V., 2012, Talitrid amphipods (Crustacea: Amphipoda: Talitridae) and the driftwood ecological niche: a morphological and molecular study, pp. 2677-2700 in Journal of Natural History 46 (43-44) on page 2693, DOI: 10.1080/00222933.2012.717971, http://zenodo.org/record/520221
Molecular systematics, phylogeny and biogeography of roaches (Rutilus, Teleostei, Cyprinidae)
No full textThe aims of the present study are: (1) to produce a phylogenetic
hypothesis for the genus Rutilus by using sequence variation of the
entire mitochondrial (mt) cytochrome b (cyt-b) gene. To accomplish
this we had sampled a total of 22 populations from the Eastern
peri-Mediterranean area and Central Europe. These include 12
species (five of which with multiple populations; Fig. 1 and Table
1) out of the 14 reported in FishBase; (2) to test whether molecular
data support the current systematics of the genus; and (3) to
produce a biogeographic hypothesis for its diversification based
on estimates of divergence times. Results will be discussed in light of the two contrasting biogeographic scenarios available for Southern
European primary freshwater fishes
Attempts to molecularly distinguish cryptic taxa in Anopheles gambiae s.s.
No full textAnalyses of inversions in polytene chromosomes indicate that, in West Africa, Anopheles gambiae (sensu stricto) may be a complex of more than a single taxonomic unit, and these units have been called chromosomal forms. In order to determine whether this genetic discontinuity extends to the rest of the genome, as would be expected if reproductive isolation exists, we have sequenced several regions of both the nuclear and mitochondrial genomes. With one exception, we were unable to identify any nucleotide sites that differentiate the chromosomal forms. The exception was the internal transcribed spacer (ITS) of the ribosomal DNA (rDNA). Three sites in this region distinguish Mopti chromosomal form from Savanna and Bamako in Mall and Burkina Faso. However, outside these two countries, the association between chromosomal form and rDNA type does not always hold. Together with the variants in the rDNA intergenic spacer (IGS) described in the accompanying papers (della Torre et al., 2001; Favia et al., 2001), we can recognize two major types of rDNA, Type I and Type II (corresponding to molecular forms S and M in della Torre et al,, 2001). Type I is widespread in West Africa and is the only type found outside of West Africa (i.e. Tanzania and Madagascar). Type II is confined to West Africa,We were unable to detect any heterozygosity for the ITS types even in five collections containing both types. A sample from the island of Sao Tome could not be classified into either Type I or Type II as the rDNA had characteristics of both. In general, our results confirm that An. gambiae is not a single pan-mictic unit, but exactly how to define any new taxa remains problematic. Finally, we have found minor variants of the major rDNA types fixed in local populations; contrary to most previous studies, this suggests restricted gene flow among populations of this species
Morphological and molecular characterization of the Roman snail Helix pomatia with data on the phylogeny of the genus Helix (Polmonata, Helicidae)
No full textGENETIC DIFFERENTIATION AND BIOGEOGRAPHY IN SOUTHERN EUROPEAN POPULATIONS OF THE GENUS SCARDINIUS (PISCES, CYPRINIDAE) BASED ON ALLOZYME DATA.
No full textLevels of genetic differentiation and variability were assessed in several populations and species belonging to the primary freshwater fish genus Scardinius by means of electrophoretic analyses of 28 enzymatic loci. We studied one population of S. acarnanicus and one of S. graecus, both endemic to Greece, seven populations of S. erythrophthalmus from Greece, Slovenia, northern and central Italy, and the single extant population of S. scardafa, a species endemic to central Italy. Patterns of genetic relationships placed the Greek species basal in the neighbour-joining (NJ) and maximum parsimony (MP) trees, S. scardafa and S. erythrophthalmus are sister species. Based on the molecular clock, the split between S. acarnanicus and S. graecus occurred around 4.3 Myr ago and the split between (S. acarnanicus, S. graecus) and (S. scardafa, S. erythrophthalmus) around 3.5 Myr ago, both after the Messinian lacustrine ‘Lago Mare’ phase of the Mediterranean. The separation between S. scardafa and S. erythrophthalmus was more recent (0.5 Myr ago) and was probably the result of confluences between adjacent river basins during the Pleistocene. Within S. erythrophthalmus, the Greek population showed a certain degree of genetic differentiation, whereas northern and central Italian populations were nearly indistinguishable. These findings demonstrate the impact of the artificial introduction of this species into central Italy, leading to the near extinction of the endemic S. scardafa
Recent expansion and relic survival: Phylogeography of the land snail genus Helix (Mollusca, Gastropoda) from south to north Europe
No full textLittle is known about the evolutionary history of Helix, despite the fact that it includes the largest land snails in the western Palaearctic, some of which (e.g. H. pomatia Linnaeus, 1758) are valuable human food. We compared two groups of Helix with apparently contrasting evolutionary histories: the widespread species H. pomatia and the group distributed along the Italian Apennine chain, a relatively unknown set of species with a restricted distribution over a range of altitudes. To reconstruct the evolutionary trajectories of these two groups, we analysed morphological (shell and genitalia) and molecular characters (mitochondrial and nuclear markers) in a total of 59 populations from northern and central Europe (H. pomatia) and along the Apennine chain (various species). We also reconstructed the phylogeny and the evolutionary history of the genus by combining our data with that currently available in the literature. We found that spatial changes did not merely imply fragmentation of populations, but also implied environmental changes (woodlands vs. grasslands) that may have triggered the observed phenotypic diversification. We also found that Anatolia is the ancestral range of Helix and is therefore an important area for the Palaearctic diversity. The results provide insights into the evolutionary history of species richness and more generally into the processes that may have shaped the distribution and diversification of these organisms across Europe and the peri-Mediterranean area
Identification and characterization of five polymorphic microsatellite loci in the freshwater copepod Hemidiaptomus gurneyi (Copepoda: Calanoida: Diaptomidae)
No full textHemidiaptomus diaptomid copepods are known to be excellent biological indicators for the highly biodiverse crustacean communities inhabiting Mediterranean temporary ponds (MTPs), an endangered inland water habitat whose conservation is considered a priority according to the “Habitat Directive” of the European Union. This study reports on the characterization of five polymorphic microsatellite loci in Hemidiaptomus gurneyi, to be used as markers for fine-scale studies on the population genetic structure and metapopulation dynamics of a typical and obligate MTP dweller. The five selected loci proved to be polymorphic in the species, with three to five polymorphic loci per studied population. Overall, mean heterozygosity scored for all loci and populations was lower than that reported for the few other diaptomid species for which microsatellite loci have been to date described; this is possibly due to the intrinsically fragmented and isolated peculiar habitat inhabited by the species. Furthermore, the presence of indels within the flanking regions of selected loci was scored.
This study, albeit confirming the technical difficulties in finding proper microsatellite markers in copepods, provides for the first time a set of useful polymorphic microsatellite loci for a Hemidiaptomus species, thus allowing the realization of finescale phylogeographic and population genetics studies of this flagship crustacean taxon for MTPs
The genetic structure and connectivity in two sympatric rodent species with different life histories are similarly affected by land use disturbances
Full text linkThe negative impact of habitat fragmentation due to human activities may be different in different species that co-exist in the same area, with consequences on the development of environmental protection plans. Here we aim at understanding the effects produced by different natural and anthropic landscape features on gene flow patterns in two sympatric species with different specializations, one generalist and one specialist, sampled in the same locations. We collected and genotyped 194 wood mice (generalist species) and 199 bank voles (specialist species) from 15 woodlands in a fragmented landscape characterized by different potential barriers to dispersal. Genetic variation and structure were analyzed in the two species, respectively. Effective migration surfaces, isolation-by-resistance (IBR) analysis, and regression with randomization were used to investigate isolation-by-distance (IBD) and the relative importance of land cover elements on gene flow. We observed similar patterns of heterozygosity and IBD for both species, but the bank vole showed higher genetic differences among geographic areas. The IBR analysis suggests that (i) connectivity is reduced in both species by urban areas but more strongly in the specialist bank vole; (ii) cultivated areas act as dispersal corridors in both species; (iii) woodlands appear to be an important factor in increasing connectivity in the bank vole, and less so in the wood mouse. The difference in dispersal abilities between a generalist and specialist species was reflected in the difference in genetic structure, despite extensive habitat changes due to human activities. The negative effects of fragmentation due to the process of urbanization were, at least partially, mitigated by another human product, i.e., cultivated terrains subdivided by hedgerows, and this was true for both species
A molecular phylogenetic framework for the evolution of parasitic strategies in cymothoid isopods (Crustacea)
Full text linkThe parasitic isopods belonging to the family Cymothoidae attach under the scales, in the gills or on the tongue of their fish hosts, exhibiting
distinctive life-histories and morphological modifications. According to conventional views, the three parasitic types (scale-, gill-, and mouthdwellers)
correspond to three distinct lineages. In this study, we have used fragments of two mitochondrial genes (large ribosomal DNA subunit,
16S rRNA, and cytochrome oxidase I) and two species for each of the three parasitic habits to present a preliminary hypothesis on the
evolutionary history of the family. Our molecular data support the monophyly of the family but suggest that – contrary to what was previously
believed – the more specialized mouth- and gill-inhabiting species are not necessarily derived from scale-dwelling ones
Specific distinction by allozimic data of sympatric species of anthophagous beetles (Coleoptera: Nitidulidae).
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