Search results for "Gene Flow"
showing 10 items of 177 documents
Biodiversity and characterization of arbuscular mycorrhizal fungi at the molecular level
1994
Biodiversity within a biological group provides the basis for distinguishing members into genera and species according to taxonomic criteria, and between individuals within a species depending on more detailed differences at the genetic level. Diversity between species occurs after a genetic barrier has been created either by a geographic or genetic impedance of gene flow. Divergence can continue by nucleotide substitutions and by mutations in a broader sense (deletions, translocations, duplications), and resulting diversity can be evaluated at the molecular level and used as a phylogenetic character. Diversity at the subspecies level is a function of both mutation rates and gene flow betwe…
Neutral modelling of agricultural landscapes by tessellation methods: the GenExP-LandSiTes software - Application to the simulation of gene flow
2010
International audience; We present a three steps approach that aimed at simulating neutral agricultural landscape models: (1) we characterized the geometry of three real field patterns; (2) we generated simulated field patterns with two tessellation methods attempting to control the value of some of the observed characteristics and, (3) we evaluated the simulated field patterns. The first two steps were integrated to the GenExP-LandSiTes software that thus simulates two-dimensional agricultural landscapes. It is written in Java, and it is freely accessible through a Gnu Public Licence. For the third step, we considered that good simulated field patterns should capture characteristics of rea…
Ex Ante evaluation of gene flow in oilseed rape with cropping system models
2013
Chapitre 4; Oilseed rape (OSR) genes can escape fields in space via pollen and seeds, and in time via volunteers resulting from seeds lost before or during oilseed rape harvest. When varieties co-exist, e.g. genetically-modified (GM) and non-GM varieties, this spatio-temporal gene flow can lead to the adventitious presence of GM seeds in non-GM harvests and thus cause financial losses for farmers and cooperatives. Gene flow depends on crop locations, succession, and management, as well as the location and management of semi-natural areas such as roadverges. The objective of this investigation was to present a simulation methodology using the spatially-explicit cropping system model GENESYS …
New polymorphic markers for genetic diversity studies in an invasive plant: the common ragweed (Ambrosia artemisiifolia L.)
2014
Common ragweed is an annual herb that belongs to the Asteraceae family. It is known as an invasive plant originating from the USA. In France the common ragweed is especially abundant in the Rhône-Alpes basin and currently spreads northwards in Burgundy. Ragweed colonizes different types of environments, such as railways, river sides, wastelands, farmlands and cultivated crops (especially sunflowers crops). Herbicide resistance to linuron, glyphosate and/or acetolactate synthase inhibitors has been reported in the USA, which complicates the chemical control of ragweed. In addition, the highly allergenic pollen of ragweed causes severe allergies. These elements make this plant a major threat …
How to manage the impact of gene flow on oilseed rape grain quality? Simulation case studies of three contrasted landscapes
2012
Abstract Grain admixture due to gene flow of oilseed rape (OSR) could be economically damaging. Different strategies are currently used or proposed to manage grain quality, ranging from homogenisation at the silo level to tactical decision rules at the field level. The relevance of these general strategies was appraised in the case of genetically modified (GM) OSR in three contrasted regions in Europe: Beauce Blesoise (France), Schleswig-Flensburg (Germany), and Fife (UK). Field patterns, crop allocation and agricultural practices were derived from existing datasets and complementary field surveys. Then a gene flow simulator was used to assess how the local contexts influenced the grain adm…
Sensitivity to oilseed rape gene flow in two European contrasted regions
2007
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Ex ante evaluation of gene flow in oilseed rape with cropping sytem models
2009
International audience
Consequences of gene flow between oilseed rape and wild radish
2013
International audience; Gene flow and introgression from crops to wild species can modify the adaptive potential and weediness of arable-land plant species. It gained recent importance with the release of genetically modified (GM) crops because of the risk of transfer of herbicide-resistance genes to related weeds. It is also a permanent possibility that could have occurred in the past with any conventional variety. In order to investigate this “normal” phenomenon and its impact, we developed three approaches in the framework of the study of gene flow between oilseed rape (Brassica napus) and wild radish (Raphanus raphanistrum). First, we compared the growth and reproduction of progeny of a…
Genome‐phenotype‐environment associations identify signatures of selection in a panmictic population of threespine stickleback
2023
Adaptive genetic divergence occurs when selection imposed by the environment causes the genomic component of the phenotype to differentiate. However, genomic signatures of natural selection are usually identified without information on which trait is responding to selection by which selective agent(s). Here we integrate whole-genome-sequencing with phenomics and measures of putative selective agents to assess the extent of adaptive divergence in threespine stickleback occupying the highly heterogeneous lake Mývatn, NE Iceland. We find negligible genome wide divergence, yet multiple traits (body size, gill raker structure and defence traits) were divergent along known ecological gradients (t…
Differences in allozyme patterns between Diaphanosoma brachyurum and Diaphanosoma mongolianum, as revealed in Central European populations
1995
Recent taxonomic revisions in the genus Diaphanosoma have made the uncertainty in species discrimination with morphological characters obvious. Therefore species characterization on a genetic basis seems to be required. Here we examined the genetic structure of two Diaphanosoma mongolianum populations and three Diaphanosoma brachyurum populations in Central Europe by allozyme electrophoresis. A genetic differentiation between both species was evident. 5 out of 9 tested loci carried diagnostic alleles. Both species differed in their habitat choice: D. mongolianum was adapted to higher trophic levels than D. brachyurum. Co-occurrence was observed in a eutrophic lake. Populations sampled from …