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Fine-scale genetic structure and gene dispersal in Centaurea corymbosa (Asteraceae), I. Pattern of pollen dispersal / Olivier J. Hardy in Journal of Evolutionary Biology, vol. 17, n°4 (Année 2004)

Public [article]  inJournal of Evolutionary Biology > vol. 17, n°4 (Année 2004) Titre : Fine-scale genetic structure and gene dispersal in Centaurea corymbosa (Asteraceae), I. Pattern of pollen dispersal Auteurs : Olivier J. Hardy, Auteur ; Santiago C. González-Martínez, Auteur ; Hélène Fréville, Auteur ; G. Boquien, Auteur ; Agnès Mignot, Auteur ; Bruno Colas, Auteur ; Isabelle Olivieri (1957-2016), Auteur Année de publication : 2004 Langues : Anglais (eng) Catégories : [Espèces (in biblio)] Centaurea corymbosa [Thèmes] Plante à forte valeur patrimoniale [Thèmes] Pollinisation, pollen, nectar Mots-clés : dispersion pollinique Résumé : "Pollen dispersal was characterized within a population of the narrowly endemic perennial herb, Centaurea corymbosa, using exclusion-based and likelihood-based paternity analyses carried out on microsatellite data. Data were used to fit a model of pollen dispersal and to estimate the rates of pollen flow and mutation/genotyping error, by developing a new method. Selfing was rare (1.6%). Pollen dispersed isotropically around each flowering plant following a leptokurtic distribution, with 50% of mating pairs separated by less than 11 m, but 22% by more than 40 m. Estimates of pollen flow lacked precision (0-25%), partially because mutations and/or genotyping errors (0.03-1%) could also explain the occurrence of offspring without a compatible candidate father. However, the pollen pool that fertilized these offspring was little differentiated from the adults of the population whereas strongly differentiated from the other populations, suggesting that pollen flow rate among populations was low. Our results suggest that pollen dispersal is too extended to allow differentiation by local adaptation within a population. However, among populations, gene flow might be low enough for such processes to occur." (source : auteurs) Note de contenu : Cette article montre que la dispersion du pollen de Centaurea corymbosa est principalement locale mais peut atteindre des distances considérables, avec des implications pour la structure génétique et la différenciation des populations. Type de publication : périodique Référence biblio : Hardy O., González-Martínez S., Fréville H., Boquien G., Mignot A., Colas B., Olivieri I., 2004 - Fine-scale genetic structure and gene dispersal in Centaurea corymbosa (Asteraceae), I. Pattern of pollen dispersal. Journal of Evolutionary Biology, 17 (4) : . ID PMB : 72266 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=72266 [article]

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Fine-Scale Genetic Structure and Gene Dispersal in Centaurea corymbosa (Asteraceae), II. Correlated Paternity Within and Among Sibships / Olivier J. Hardy in Genetics, vol. 168, n°3 (Année 2004)  

Public [article]  inGenetics > vol. 168, n°3 (Année 2004) . - pp. 1601-14 Titre : Fine-Scale Genetic Structure and Gene Dispersal in Centaurea corymbosa (Asteraceae), II. Correlated Paternity Within and Among Sibships Auteurs : Olivier J. Hardy, Auteur ; Santiago C. González-Martínez, Auteur ; Bruno Colas, Auteur ; Hélène Fréville, Auteur ; Agnès Mignot, Auteur ; Isabelle Olivieri (1957-2016), Auteur Année de publication : 2004 Article en page(s) : pp. 1601-14 Langues : Anglais (eng) Catégories : [Espèces (in biblio)] Centaurea corymbosa [Thèmes] Conservation Mots-clés : analyse génétique  microsatellite  dispersion pollinique Résumé : "The fine-scale pattern of correlated paternity was characterized within a population of the narrow-endemic model plant species, Centaurea corymbosa, using microsatellites and natural progeny arrays. We used classical approaches to assess correlated mating within sibships and developed a new method based on pairwise kinship coefficients to assess correlated paternity within and among sibships in a spatio-temporal perspective. We also performed numerical simulations to assess the relative significance of different mechanisms promoting correlated paternity and to compare the statistical properties of different estimators of correlated paternity. Our new approach proved very informative to assess which factors contributed most to correlated paternity and presented good statistical properties. Within progeny arrays, we found that about one-fifth of offspring pairs were full-sibs. This level of correlated mating did not result from correlated pollen dispersal events (i.e., pollen codispersion) but rather from limited mate availability, the latter being due to limited pollen dispersal distances, the heterogeneity of pollen production among plants, phenological heterogeneity and, according to simulations, the self-incompatibility system. We point out the close connection between correlated paternity and the “TwoGener” approach recently developed to infer pollen dispersal and discuss the conditions to be met when applying the latter." (source : auteurs) Note de contenu : Cet article se concentre sur la structure génétique fine et les mécanismes de dispersion des gènes au sein d'une population de Centaurea corymbosa, une espèce de plante endémique à aire de répartition restreinte. L'étude utilise des microsatellites et des analyses de progéniture naturelle pour évaluer la paternité corrélée à la fois au sein des fratries et entre elles, sur différentes échelles spatiales et temporelles. Il vise à comprendre les schémas de dispersion génétique et les modes de reproduction de Centaurea corymbosa afin d'élaborer des stratégies de conservation permettant de maintenir sa diversité génétique et d'assurer sa survie à long terme. Type de publication : périodique Référence biblio : Hardy O., González-Martínez S., Colas B., Fréville H., Mignot A., Olivieri I., 2004 - Fine-Scale Genetic Structure and Gene Dispersal in Centaurea corymbosa (Asteraceae), II. Correlated Paternity Within and Among Sibships. Genetics, 168 (3) : 1601-14. ID PMB : 72265 En ligne : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1448787/ Format de la ressource électronique : document Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=72265 [article]

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• Fine-scale genetic structure and gene dispersal in Centaurea corymbosa (Asteraceae), I. Pattern of pollen dispersal / Olivier J. Hardy in Journal of Evolutionary Biology, vol. 17, n°4 (Année 2004)

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Microsatellite allele sizes : a simple test to assess their significance on genetic differentiation / Olivier J. Hardy in Genetics, vol. 163, n°4 (Année 2003)

Public [article]  inGenetics > vol. 163, n°4 (Année 2003) . - pp. 1467-82 Titre : Microsatellite allele sizes : a simple test to assess their significance on genetic differentiation Auteurs : Olivier J. Hardy, Auteur ; Nathalie Charbonnel, Auteur ; Hélène Fréville, Auteur ; Myriam Heuertz, Auteur Année de publication : 2003 Article en page(s) : pp. 1467-82 Langues : Anglais (eng) Mots-clés : diversité génétique  marqueur génétique  microsatellite Résumé : "The mutation process at microsatellite loci typically occurs at high rates and with stepwise changes in allele sizes, features that may introduce bias when using classical measures of population differentiation based on allele identity (e.g., F(ST), Nei's Ds genetic distance). Allele size-based measures of differentiation, assuming a stepwise mutation process [e.g., Slatkin's R(ST), Goldstein et al.'s (deltamu)(2)], may better reflect differentiation at microsatellite loci, but they suffer high sampling variance. The relative efficiency of allele size- vs. allele identity-based statistics depends on the relative contributions of mutations vs. drift to population differentiation. We present a simple test based on a randomization procedure of allele sizes to determine whether stepwise-like mutations contributed to genetic differentiation. This test can be applied to any microsatellite data set designed to assess population differentiation and can be interpreted as testing whether F(ST) = R(ST). Computer simulations show that the test efficiently identifies which of F(ST) or R(ST) estimates has the lowest mean square error. A significant test, implying that R(ST) performs better than F(ST), is obtained when the mutation rate, mu, for a stepwise mutation process is (a) >/= m in an island model (m being the migration rate among populations) or (b) >/= 1/t in the case of isolated populations (t being the number of generations since population divergence). The test also informs on the efficiency of other statistics used in phylogenetical reconstruction [e.g., Ds and (deltamu)(2)], a nonsignificant test meaning that allele identity-based statistics perform better than allele size-based ones. This test can also provide insights into the evolutionary history of populations, revealing, for example, phylogeographic patterns, as illustrated by applying it on three published data sets." (source : auteurs) Note de contenu : Cet article discute de l'utilisation des marqueurs génétiques microsatellites pour évaluer la différenciation génétique entre populations. Le principal objectif de l'étude est de proposer un test simple basé sur la permutation des tailles des allèles pour déterminer si les mutations de type stepwise (à pas fixes) contribuent à la différenciation génétique. Type de publication : périodique Référence biblio : Hardy O., Charbonnel N., Fréville H., Heuertz M., 2003 - Microsatellite allele sizes : a simple test to assess their significance on genetic differentiation. Genetics, 163 (4) : 1467-82. ID PMB : 72267 DOI : 10.1093/genetics/163.4.1467 Permalink : http://www.cbnbrest.fr/catalogue_en_ligne/index.php?lvl=notice_display&id=72267 [article]

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