Search results for "population genetics."
showing 10 items of 248 documents
Eight microsatellite markers isolated from common ragweed (Ambrosia artemisiifolia L.) and cross-amplification with herbarium specimens
2009
; Eight microsatellite markers were developed for population genetic analyses of the common ragweed, Ambrosia artemisiifolia. Markers were tested for amplification with three populations (two recent populations from France and North America, and one historical population from herbarium specimens). These loci revealed a high level of genetic variability (5-19 alleles per locus; expected heterozygosity, 0.48-0.92). No significant deviation from Hardy-Weinberg equilibrium and no linkage disequilibrium were observed. The data thus demonstrate their utility as efficient genetic markers for determining the genetic diversity, population differentiation, and gene flow among invasive, native, and h…
Identification of Traits Implicated in the Rhizosphere Competence of Fluorescent Pseudomonads: Description of a Strategy Based on Population and Mode…
2009
E-book; International audience; The lack of consistency of the beneficial effects of inoculated fluorescent pseudomonads has often been related to their bad survival in the rhizosphere. In this review, we describe the strategy followed over the last decade to study traits involved in the rhizosphere competence of these bacteria. The diversity of indigenous populations associated with plant roots was first compared to that of populations associated with uncultivated soils in order to identify traits that discriminate these populations. The involvement of these bacterial traits in the rhizosphere competence was then assessed by comparing the competitiveness of a wild-type strain to that of mu…
Fragmentation des habitats et interactions hôtes-parasites
2021
Habitat fragmentation is one of the main threats to global biodiversity and despite an abundant literature on the impact of fragmentation on species abundance and diversity, the consequences of this global change in terms of ecological and evolutionary processes remain poorly understood. Beyond their direct contribution to biodiversity, as species-rich category of organisms, parasites could be involved in biodiversity change as key actors of ecological and evolutionary processes. The present work aims to understand the effect of forest fragmentation on host-parasite interactions. It is based on a large sampling carried out in the Lesser Antilles and in French Guiana, and allowing the obtent…
Population Structure and Comparative Genome Hybridization of European Flor Yeast Reveal a Unique Group of Saccharomyces cerevisiae Strains with Few G…
2014
Wine biological aging is a wine making process used to produce specific beverages in several countries in Europe, including Spain, Italy, France, and Hungary. This process involves the formation of a velum at the surface of the wine. Here, we present the first large scale comparison of all European flor strains involved in this process. We inferred the population structure of these European flor strains from their microsatellite genotype diversity and analyzed their ploidy. We show that almost all of these flor strains belong to the same cluster and are diploid, except for a few Spanish strains. Comparison of the array hybridization profile of six flor strains originating from these four co…
Population genetics on Ambrosia genus: past, present and future
2014
National audience; A new Task Force within the COST-SMARTER has recently been created. This group is composed of population genetics experts from five European countries in charge of focusing on “Genetics on Ambrosia” (Austria, France, Germany, Hungary, Sweden). Their mission was to review molecular methods used in published genetics studies on common ragweed and to discuss about future projects. Two different types of molecular markers are generally used in the literature to investigate the genetic structure within and between introduced and/or native populations of common ragweed: microsatellite markers and amplified fragment length polymorphism (AFLP). These methods permit the researcher…
A STUDY OF POPULATION GENETICS IN THE EUROPEAN LOBSTER, HOMARUS GAMMARUS (DECAPODA, NEPHROPIDAE)
2001
By means of an RAPD analysis, the degree of genetic variation in the European lobster, Homarus gammarus, was assessed. We focused our attention on the Helgoland population, which is isolated by its geographical location. By comparison with seven other European lobster populations we demonstrated that the Helgoland lobster is genetically widely separated from other European lobster stocks. However, all populations investigated showed high values of genetic distance, indicating that genetic exchange among European populations of Homarus gammarus may be restricted. The European lobster populations appeared to be isolated by distance since the pattern of genetic relationships reflects their geo…
Comparative evolution of P–M system and infection by the sigma virus in French and Spanish populations ofDrosophila melanogaster
1992
SummaryIn 1983, an extensive survey of populations ofD. melanogasterwas started in a southern French region (Languedoc) in two non-Mendelian systems: the P–M system of transposable elements and the hereditary Rhabdovirus sigma. Unexpectedly fast-evolving phenomena were observed and interesting correlations were noted, giving similar geographical pattern to the region in both systems. For these reasons, the analysis was continued and extended towards the north (Rhône Valley) and the south (Spain). In the P–M system, all the Languedoc populations evolved from 1983 to 1991 towards the Q type which is characteristic of the Rhône Valley populations. In contrast, M′ strains are currently observed…
The effect of periodic bottlenecks on the competitive ability of Drosophila pseudoobscura lines.
1993
Competition experiments between several Drosophila pseudoobscura strains that were previously subjected to periodic bottlenecks of different sizes and D. willistoni have been carried out. Contrary to previous results with these two species, where stable coexistence was detected, populations of D. pseudoobscura displaced D. willistoni in a few generations. By using a relative fitness measure, the control lines (that had not gone through bottlenecks) outcompeted D. willistoni faster than bottlenecked lines. One of these, corresponding to the minimum possible bottleneck size of one pair, also shows significantly lower relative fitness than the other strains. These results are discussed in rela…
Data Evaluation in Population Genetics and Evolution
1994
Isozymes maybe generated by different enzyme loci (a) (isoenzymes), (b) alleles of a locus (allozymes) or (c) post-translational modifications (secondary isozymes). Differences in isozyme numbers and isoenzyme properties can be used for evolutionary studies. But quantitations of genetic variation among or within populations are obtainable only from allozyme frequencies.