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Enzyme Loci (enzyme + locus)
Selected AbstractsGenetic subdivision, glacial refugia and postglacial recolonization in the golden-striped salamander, Chioglossa lusitanica (Amphibia: Urodela)MOLECULAR ECOLOGY, Issue 6 2000J. Alexandrino Abstract The golden-striped salamander (Chioglossa lusitanica) is an ecologically specialized species, endemic to north-western Iberia. Patterns of genetic variation were assessed at seven polymorphic enzyme loci and one mitochondrial DNA (mtDNA) marker (cytochrome b) in 17 populations across its range. Estimates of enzyme genetic diversity revealed a high degree of genetic subdivision (FST = 0.68), mainly attributable to the existence of two groups of populations. The groups were located, respectively, north and south of the Mondego River, indicating that this river coincided with a major historical barrier to gene flow. A significant decrease in genetic variability from the Mondego northwards was associated with the Douro and Minho rivers. mtDNA sequence variation revealed a congruent pattern of two haplotype groups (d = 2.2%), with a geographical distribution resembling that of allozymes. The pattern and depth of genetic variation is consistent with the following hypotheses: (i) subdivision of an ancestral range of the species prior to the middle Pleistocene; (ii) secondary contact between populations representing historical refugia; (iii) relatively recent range expansion giving rise to the northern part of the species range; and (iv) loss of genetic variation through founder effects during range expansion across major rivers. [source] Genetic differentiation among the Maculinea species (Lepidoptera: Lycaenidae) in eastern Central EuropeBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2007KATALIN PECSENYE The present study aimed to analyse the level of genetic variation in the eastern Central European (Slovenia, Hungary, and Romania/Transylvania) populations of the Large Blues (Maculinea) to analyse the pattern of differentiation both between and within the species. One objective was to compare the level of differentiation between the two disputed species (Maculinea alcon and Maculinea rebeli) with that among the other species. Imagos were collected from 23 localities in eastern Central Europe in 2002. Enzyme polymorphism was analysed using polyacrylamide gel electrophoresis. Fourteen enzyme loci were studied in all samples. In the analysis of the data, F -statistics and Nei's genetic distances were calculated and a dendrogram (unweighted pair group method with arithmetic mean) was constructed on the basis of the distance matrix. A multivariate analysis of variance was performed to study the pattern of genetic differentiation among the samples. Principal component analysis analysis was also carried out using the allele frequency data of the samples. Our results indicated that the large blues are generally less polymorphic than other European lycaenid butterflies studied. At the same time, the level of genetic differentiation was high, even among local populations within the species. A low level of genetic variation within the populations coupled with strong differentiation among them implies the effect of genetic drift. Strong genetic differentiation of four Maculinea species (M. alcon, Maculinea teleius, Maculinea nausithous, and Maculinea arion) was confirmed. Significant differentiation was not found between M. alcon and M. rebeli. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 91, 11,21. [source] The species delimitation problem applied to the Agabus bipustulatus complex (Coleoptera, Dytiscidae) in north ScandinaviaBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2001MARCUS K. DROTZ Agabus bipustulatus (Linnaeus) is one of the most common aquatic beetles in Europe. Two species have been traditionally recognized within the Palaearctic Agabus bipustulatus complex (Coleoptera, Dytiscidae) in Scandinavia: a lowland form A. bipustulatus and a high-altitude form A. solieri Aube. The specific status of solieri has been debated for more than a century but no quantitative investigation has been made to evaluate the status of this taxon. In this study we show that there is no clear-cut delimitation between the two forms, either morphological or genetic, across an altitudinal gradient in north Scandinavia. Morphological differences between 22 populations were analysed separately for each sex with both thin-plate splines relative warp analysis and ,classical-length' morphometries. Genetic variation at five polymorphic enzyme loci was analysed among seven populations. The morphological studies showed gradual variation correlated with altitude, in particular in the character that is traditionally used to separate solieri and bipustulatus, and in both the beetles' morphometric size and the lateral width of the metasternal plate, which is connected to flight capacity. The genetic study indicates that the a-Gpdh enzyme locus, which is involved in the transfer of energy to the flight muscles, is evidently subject to directional selection. Only minor population differences were observed without this system. Subdivision was found in some populations and was probably caused by migration from outside or within the local population. The overall conclusion is that there is no clear-cut species delimitation between A. bipustulatus and A. solieri in north Scandinavia. This indicates that A. solieri is a cold-adapted altitudinal form of the variable A. bipustulatus; additional support for this is the finding of solieri,look alikes' in cold springs in areas normally inhabited by bipustulatus. [source] Temporal variation in the genetic structure of host-associated populations of the small ermine moth Yponomeuta padellus (Lepidoptera, Yponomeutidae)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2000LÉON E. L. RAIJMANN Temporal changes in allele frequencies were studied in host-associated populations of the small ermine moth Yponomeuta padellus. At one site, populations from three host plants (Sorbus aucuparia, Amelanchier larnarckii, and Crataegus spp.) were sampled annually during a four-year-period and analysed with 20 polymorphic allozyme markers. At two other sites, allele frequencies at 5- 6 enzyme loci of Y. padellus populations from two different host plants were also tested for consistency over a 13-year-pcriod. Significant allele frequency changes occurred in the short-term analysis, whereas allele frequencies remained relatively stable through time in the long-term analyses. Furthermore, allele frequencies of Y. padellus populations from Crataegus spp. were relatively stable compared to the other host populations. The role of the agents responsible for the observed patterns is discussed. [source] The adaptive role of Phosphoglucomutase and other allozymes in a marine snail across the vertical rocky-shore gradientBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2009JUAN GALINDO Natural selection can play an important role in the maintenance of genetic polymorphisms, despite ongoing gene flow. In the present study, we use previously analysed allozymic loci and perform an FST outlier-based analysis to detect the signatures of divergent selection between sympatric ecotypes of the marine snail Littorina saxatilis at different localities. The results obtained show that different allozyme polymorphisms are affected (directly or indirectly) by selection at distinct geographical regions. The Phosmogluco mutase-2 locus was the best candidate for adaptation and further biochemical analyses were performed. The kinetic properties of the three more common genotypes of Pgm-2 were studied. The results obtained are concordant with two alternative hypotheses: (1) natural selection is acting directly on this locus or, more probably, (2) selection is affecting a genomic region tightly linked to the enzyme locus. In both cases, the known existence of a parallel and partially independent origin of these ecotypes would explain why different candidate loci were detected in different localities. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 225,233. [source] The species delimitation problem applied to the Agabus bipustulatus complex (Coleoptera, Dytiscidae) in north ScandinaviaBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2001MARCUS K. DROTZ Agabus bipustulatus (Linnaeus) is one of the most common aquatic beetles in Europe. Two species have been traditionally recognized within the Palaearctic Agabus bipustulatus complex (Coleoptera, Dytiscidae) in Scandinavia: a lowland form A. bipustulatus and a high-altitude form A. solieri Aube. The specific status of solieri has been debated for more than a century but no quantitative investigation has been made to evaluate the status of this taxon. In this study we show that there is no clear-cut delimitation between the two forms, either morphological or genetic, across an altitudinal gradient in north Scandinavia. Morphological differences between 22 populations were analysed separately for each sex with both thin-plate splines relative warp analysis and ,classical-length' morphometries. Genetic variation at five polymorphic enzyme loci was analysed among seven populations. The morphological studies showed gradual variation correlated with altitude, in particular in the character that is traditionally used to separate solieri and bipustulatus, and in both the beetles' morphometric size and the lateral width of the metasternal plate, which is connected to flight capacity. The genetic study indicates that the a-Gpdh enzyme locus, which is involved in the transfer of energy to the flight muscles, is evidently subject to directional selection. Only minor population differences were observed without this system. Subdivision was found in some populations and was probably caused by migration from outside or within the local population. The overall conclusion is that there is no clear-cut species delimitation between A. bipustulatus and A. solieri in north Scandinavia. This indicates that A. solieri is a cold-adapted altitudinal form of the variable A. bipustulatus; additional support for this is the finding of solieri,look alikes' in cold springs in areas normally inhabited by bipustulatus. [source] | ||||||||||