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SIMON BLANCHET OLIVIER REY PAULINE BERTHIER SOVAN LEK GERALDINE LOOT 《Molecular ecology》2009,18(6):1112-1123
Identifying the processes maintaining genetic variability in wild populations is a major concern in conservation and evolutionary biology. Parasite-mediated selection may strongly affect genetic variability in wild populations. The inbreeding depression theory predicts that directional selection imposed by parasites should act against the most inbred hosts, thus favouring genetic diversity in wild populations. We have tested this prediction by evaluating the strength and shape of the relationship between the load of a harmful fin-feeder ectoparasite ( Tracheliastes polycolpus ) and the genome-wide genetic diversity (i.e. heterozygosity measured at a set of 15 microsatellites) of its fish host, the rostrum dace ( Leuciscus leuciscus ). Contrary to expectation, we found a nonlinear relationship between host genetic diversity and ectoparasite load, with hosts that were either homozygous or heterozygous harbouring significantly fewer parasites than hosts with an intermediate level of heterozygosity. This relationship suggests that parasites could increase the variance of global heterozygosity in this host population through disruptive selection on genetic diversity. Moreover, when genetic diversity was measured at each locus separately, we found two very strong positive associations between host genetic diversity and the ectoparasite load. This latter result has three main implications: (i) genome-wide effect cannot alone explain the nonlinear relationship between global heterozygosity and ectoparasite load, (ii) negative non-additive allelic interactions (i.e. underdominance) may be a mechanism for resisting ectoparasite infection, and (iii) ectoparasites may favour homozygosity at some loci in this host population. 相似文献
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FRANCE DARDEAU ALEXANE BERTHIER FLORIE MIARD JEAN‐PHILIPPE CHRISTIDÈS MURIEL FEINARD‐DURANCEAU FRANCK BRIGNOLAS DAVID GIRON FRANÇOIS LIEUTIER AURÉLIEN SALLÉ 《Ecological Entomology》2015,40(6):814-822
1. Phytophagous insects frequently manipulate their host‐plant to improve their immediate environment. This generally implies substantial modifications of host metabolism, and sometimes an alteration of nitrogen allocation within the host‐plant. However, the outcome of plant manipulation on amino acid or protein content can be modulated by environmental factors and host‐plant traits. 2. It was investigated whether the pseudogall induced by the aphid Phloeomyzus passerinii (Signoret) (Aphididae: Phloeomyzinae) in the bark of its host‐plant affects the amino acid content in bark tissues, and whether the strength of the modification is modulated by the fertilisation regime and/or the resistance level of the host‐plant. The development of aphid colonies on a resistant and a susceptible poplar genotype, under three fertilisation regimes, was studied. After the development of colonies, the free and protein‐bound amino acid content of the infested bark were quantified. 3. Fertilisation enhanced poplar growth and increased the free amino acid content of bark tissues. Infestation also triggered accumulations of both free and protein‐bound amino acids in the feeding sites, but in the susceptible genotype only. The increase in amino acid content was more pronounced when fertilisation was low, and fertilisation did not enhance aphid development. 4. In conclusion, infestation by P. passerinii triggers an accumulation of amino acids, but the effect is influenced by both the fertilisation regime and the resistance level of the host‐plant. This suggests that P. passerinii could affect the allocation of nutrients within trees during outbreaks. 相似文献
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K. BERTHIER M. GALAN A. WEBER A. LOISEAU J. F. COSSON 《Molecular ecology resources》2004,4(4):620-622
We isolated and characterized nine polymorphic dinucleotide microsatellite loci in the fossorial vole Arvicola terrestris Scherman (Shaw). A multiplex panel comprising all nine loci was developed and its application to a set of 31 individuals allowed clear and easy characterization of allele sizes. The number of alleles range from three to 14 per locus with the observed heterozygosity ranging from 0.42 to 0.90. These markers will be useful for analysis of questions concerning population genetic structure and reproductive behaviour. 相似文献
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SERGE BERTHIER ERIC CHARRON JULIE BOULENGUEZ 《Insect Science》2006,13(2):145-158
The morphological structure and optical properties of the wings of 14 species of Morphidae have been investigated. Most of the scales of the iridescent species of Morphidae (Lepidoptera) present a very particular structure. The ground scales, responsible for the major part of the optical properties, are covered by a very regular set of longitudinal ridges. The ridges themselves are constituted by a superposition of lamellae that act locally as a multilayered structure. This very specific morphology leads to both interferences and diffraction effects. The first one is responsible of the brilliant blue coloration of the males, while the second one diffracts this colored light at a very large angle. These two phenomena give to the butterfly a very effective long-range communication system. The morphological characteristics of the scales of the various species are presented in detail. Two types of optical measurement were performed on the iridescent wings of 14 different species of Morphidae: spectroscopic measurements under various incidences and gonioscopic measurements for a given incidence angle and wavelength. The first allows a determination of the index of refraction of the cuticular material. The second leads to the drawing of spatial diffraction maps. It shows that most of the reflected light is diffracted laterally over a very large angle (90° 〈 0 〈 120°, according to the different species) and that this repartition depends of the polarization of incident light. As predicted by previous calculations, the dissymmetric structure of the ridge is responsible for the separation of the polarization modes in the various diffraction orders. 相似文献
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KARINE BERTHIER MARIE‐PIERRE CHAPUIS SEYED M. MOOSAVI DONYA TOHIDI‐ESFAHANI GREGORY A. SWORD 《Systematic Entomology》2011,36(2):285-299
We examined the level of intra‐individual variation in a region of the mitochondrial genome coding for cytochrome oxydase 1 (COI) in two grasshopper species using a clone‐and‐sequence analysis of hundreds of sequences. In both Locusta migratoria and Chortoicetes terminifera, we found that 60–65% of the clones were unique COI‐like sequences. Among these COI‐like sequences, 70–75% diverged by less than 1% from the real mitochondrial haplotypes, and were likely to represent microheteroplasmic molecules. About 20% of the COI‐like sequences diverged by more than 9% from the mitochondrial haplotypes, and generally included stop codons, suggesting that these sequences were nuclear mitochondrial pseudogenes (NUMTs). Only six sequences, diverging by 2–6% from the mitochondrial haplotypes, were identified as potentially misleading in phylogenetic studies. In addition, we found that five sequences from C. terminifera were associated with mobile elements or repetitive DNA families. 相似文献
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A multiplex panel of microsatellite markers for widespread sub‐Saharan rodents of the genus Mastomys
M. GALAN W. F. VAN HOOFT D. LEGRAND K. BERTHIER A. LOISEAU L. GRANJON J. F. COSSON 《Molecular ecology resources》2004,4(3):321-323
We isolated and characterized 12 polymorphic microsatellite loci in the sub‐Saharan rodent Mastomys huberti. We tested cross‐species amplification of all these loci in three closely related Mastomys species: M. coucha, M. erythroleucus and M. natalensis. Multiplex panels comprising 11 loci were developed and their application to a set of individuals in each species allowed clear and easy characterization of allele sizes. Statistics from 31 M. huberti coming from one locality in Mali showed no deviation from Hardy–Weinberg equilibrium except for one locus, and no significant linkage disequilibria between loci. 相似文献
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