Search results for "genetic distance"
showing 10 items of 62 documents
The effect of inbreeding rate on fitness, inbreeding depression and heterosis over a range of inbreeding coefficients
2014
Understanding the effects of inbreeding and genetic drift within populations and hybridization between genetically differentiated populations is important for many basic and applied questions in ecology and evolutionary biology. The magnitudes and even the directions of these effects can be influenced by various factors, especially by the current and historical population size (i.e. inbreeding rate). Using Drosophila littoralis as a model species, we studied the effect of inbreeding rate over a range of inbreeding levels on (i) mean fitness of a population (relative to that of an outbred control population), (ii) within‐population inbreeding depression (reduction in fitness of offspring fro…
Molecular barcoding for central-eastern European Crioceris leaf-beetles (Coleoptera: Chrysomelidae)
2011
Abstract Among Crioceris leaf-beetles, the two most widespread species (Crioceris asparagi and C. duodecimpunctata) are serious invasive plant pests, while another two (C. quatuordecimpunctata and C. quinquepunctata) are rare species restricted to steppe-like habitats in Eurasia. The aim of the research was to check the genetic distinctiveness of these four species and develop barcodes for their molecular identification using the mitochondrial Cytochrome Oxidase I (COI) gene and two nuclear markers: Elongation Factor 1-α (EF1-α) and Internal Transcribed Spacer 1 (ITS1). The identification of each species was possible and reliable with the use of COI and ITS1 markers. EF1-α was omitted in an…
Phylogeny and quaternary history of the European montane/alpine endemicSoldanella(Primulaceae) based on ITS and AFLP variation
2001
Soldanella contains 16 species of herbaceous perennials that are endemic to the central and south European high mountains. The genus is ecogeographically subdivided into forest/montane and alpine species. Evolutionary relationships and large-scale biogeographic patterns were inferred from parsimony analyses of the internal transcribed spacer (ITS) regions of nuclear ribosomal DNA, and genetic distance analyses based on amplified fragment length polymorphism (AFLP) markers. The ITS region proved useful for examining subgeneric relationships and testing hypotheses on genus-wide divergence times, whereas the AFLP markers were suitable for studying relationships among closely related taxa and b…
Gel-electrophoretic description of European populations ofTerellia virens (Loew) (Diptera, Tephritidae); implications for its use as an agent for the…
1991
Allozyme frequencies of 15 enzyme loci, 14 of which were polymorphic, were used to characterize sevenTerellia virens populations originating from three allopatrically distributedCentaurea species. The two populations whose origins were geographically furthest apart, from Israel (onC. iberica) and from Switzerland (onC. vallesiaca), showed relatively high values of genetic distance from the 5 populations sampled in Austria and Hungary (onC. maculosa) (Nei's D>0.07). The latter five displayed a high degree of genetic similarity. No diagnostic (fixed) allelic differences were observed between these three groups ofT. virens populations, but they could be well characterized by significant differ…
Crocidura cossyrensis Contoli, 1989 (Mammalia, Soricidae): karyotype, biochemical genetics and hybridization experiments
2004
The shrew Crocidura cossyrensis Contoli, 1989 from Pantelleria (I), a Mediterranean island 100 km south of Sicily and 70 km west from Tunisia, was investigated in order to understand its origin and its relationship with C. russula from Tunisia, Morocco and Switzerland. With the exception of a single heterozygote centric fusion, C. cossyrensis had a karyotype identical with that of C. russula from Tunisia (2N = 42, NF = 70 to 72), but it differed from C. russula from Morocco and Switzerland (2N = 42, NF = 60). The former have 5-6 pairs of chromosomes with small arms that are acrocentric in the latter. Genetic comparisons with allozyme data revealed small genetic distance (0.04) between C. co…
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…
Genetic diversity in Sicilian populations of Quercus ilex (Fagaceae)
2013
Raimondo, F. M., Scialabba, A., Guarino, R. & Spallino, R. E.: Genetic diversity in Sicilian populations of Quercus ilex (Fagaceae). — Fl. Medit. 23: 245-253. 2013. — ISSN: 1120-4052 printed, 2240-4538 online. Recent studies on the genetic structure of the Italian populations of Quercus ilex demonstrated their high diversity, particularly in the Sicilian metapopulation. In order to check if the holm oak stands in the mountains of NW Sicily could have some relationship with Q. ilex subsp. ballota (distributed in Spain and NW Africa), 26 specimens from the Sicilian most distinctive Q. ilex populations have been compared with some representative populations of the Italian Peninsula, North Afri…
Genetic Structure of the Limecola Balthica Population in the Gulf of Riga, Baltic Sea
2020
Abstract Samples of Limecola balthica with normal and deformed shells were collected from ten sites throughout the Gulf of Riga. Genetic diversity was evaluated by the retrotransposon-based iPBS method. Samples had close mutual genetic distances, which showed that all of them belong to one wider population of the Gulf of Rīga. No direct relationship between the activity of retrotransposons and deformation of shells was found.
Microgeographic Variation of Genetic Polymorphism in Argyresthia mendica (Lep.: Argyresthiidae)
1988
Field studies on the genetic structure of populations show a considerable amount of heterogeneity in space and time. In many cases, these heterogeneities can be related to structures in the environment, such as properties of soil, availability of special food resources, topographic conditions or climate. In other cases the genetic structure can be explained by properties of the plant and animal species under study, e.g. ability and speed of migration and colonization (Karlin and Nevo 1976; Endler 1977; Nevo 1978; Nevo and Yang 1979; Nevo et al. 1981; Seitz and Komma 1984; Wohrmann 1984).
Intraspecific variation within Phlebotomus sergenti Parrot (1917) (Diptera: Psychodidae) based on mtDNA sequences in Islamic Republic of Iran.
2007
An intraspecific study on the morphological and molecular characteristics of Phlebotomus sergenti s.l., the main vector of Leishmania tropica, was performed on 28 Iranian populations from 11 provinces and a few samples from Greece, Morocco, Lebanon, Turkey, Pakistan, and Syria. Three morphotypes were identified as A, B and C, with some intermediate forms in the samples under investigation. Based on the number of setae and the width of basal lobe of coxite, differences between A and B morphotypes were highly significant. Excluding one unusual haplotype, sequence analysis of ∼439 bp of mtDNA (a fragment of cytochromeB gene, tRNA for serine gene, and a fragment of NADH1 gene) revealed a 6–7% g…