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Auteur (down) Viricel, A.; Simon-Bouhet, B.; Ceyrac, L.; Dulau-Drouot, V.; Berggren, P.; Amir, O.A.; Jiddawi, N.S.; Mongin, P.; Kiszka, J.J.
Titre Habitat availability and geographic isolation as potential drivers of population structure in an oceanic dolphin in the Southwest Indian Ocean Type Article scientifique
Année 2016 Publication Revue Abrégée Mar. Biol.
Volume 163 Numéro 10 Pages 219
Mots-Clés biologically meaningful; bottle-nosed dolphins; genetic differentiation; marine populations; megaptera-novaeangliae; microsatellite loci; mozambique channel; spinner dolphins; stenella-longirostris; tursiops-truncatus
Résumé Delphinid populations show highly variable patterns of genetic diversity and population structure. Previous studies indicate that habitat discontinuities and geographic isolation are major drivers of population division in cetaceans. Spinner dolphins (Stenella longirostris) are distributed in all tropical oceans, but they are particularly common around islands and atolls. This species occurs in shallow waters at daytime to rest and socialise, and feeds on offshore mesopelagic prey overnight. Here, we investigated the genetic population structure of spinner dolphins in the Southwest Indian Ocean along a west-east geographic gradient, from eastern Africa to the Mascarene archipelago. We combined analyses of 12 microsatellite loci, mtDNA control region sequences, and sighting data to assess genetic differentiation and characterise habitat preferences of these populations. Significant genetic structure among the three sampled sites (Zanzibar, Mayotte and La Reunion) was observed using both types of molecular markers. Overall, our results indicate that geographic isolation and potentially other factors, such as shallow-water habitats to rest and socialise, may be important drivers of the genetic population structure of insular spinner dolphins in this region.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0025-3162 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1700
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Auteur (down) Reichel, K.; Masson, J.-P.; Malrieu, F.; Arnaud-Haond, S.; Stoeckel, S.
Titre Rare sex or out of reach equilibrium? The dynamics of F-IS in partially clonal organisms Type Article scientifique
Année 2016 Publication Revue Abrégée BMC Genet.
Volume 17 Numéro Pages 76
Mots-Clés consequences; diversity; evolution; genetic diversity; genetic-structure; Heterozygote excess; hybridization; Inbreeding coefficient; loci; Mating system; microsatellite primers; mutation; Parthenogenesis; Partial asexuality; population-genetics; reproduction
Résumé Background: Partially clonal organisms are very common in nature, yet the influence of partial asexuality on the temporal dynamics of genetic diversity remains poorly understood. Mathematical models accounting for clonality predict deviations only for extremely rare sex and only towards mean inbreeding coefficient (F-IS) over bar < 0. Yet in partially clonal species, both F-IS < 0 and F-IS > 0 are frequently observed also in populations where there is evidence for a significant amount of sexual reproduction. Here, we studied the joint effects of partial clonality, mutation and genetic drift with a state-and-time discrete Markov chain model to describe the dynamics of F-IS over time under increasing rates of clonality. Results: Results of the mathematical model and simulations show that partial clonality slows down the asymptotic convergence to F-IS = 0. Thus, although clonality alone does not lead to departures from Hardy-Weinberg expectations once reached the final equilibrium state, both negative and positive F-IS values can arise transiently even at intermediate rates of clonality. More importantly, such “transient” departures from Hardy Weinberg proportions may last long as clonality tunes up the temporal variation of F-IS and reduces its rate of change over time, leading to a hyperbolic increase of the maximal time needed to reach the final mean (F-IS,F-infinity) over bar value expected at equilibrium. Conclusion: Our results argue for a dynamical interpretation of F-IS in clonal populations. Negative values cannot be interpreted as unequivocal evidence for extremely scarce sex but also as intermediate rates of clonality in finite populations. Complementary observations (e.g. frequency distribution of multiloci genotypes, population history) or time series data may help to discriminate between different possible conclusions on the extent of clonality when mean (F-IS) over bar values deviating from zero and/or a large variation of F-IS over loci are observed.
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Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1471-2156 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1648
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Auteur (down) Pirog, A.; Jaquemet, S.; Soria, M.; Magalon, H.
Titre First evidence of multiple paternity in the bull shark (Carcharhinus leucas) Type Article scientifique
Année 2017 Publication Revue Abrégée Mar. Freshw. Res.
Volume 68 Numéro 1 Pages 195-201
Mots-Clés brown smoothhound shark; convenience polyandry; genetic benefits; hammerhead shark; mating-behavior; microsatellite; microsatellite null alleles; mustelus-henlei; paternity test; polyandry; population sizes; triaenodon-obesus; whitetip reef shark
Résumé The present study assessed the occurrence of multiple paternity in four litters of bull shark Carcharhinus leucas (n = 5, 8, 9 and 11 embryos) sampled at Reunion Island in the Western Indian Ocean. Using 21 microsatellite loci, we revealed that two litters were generated from two sires each, demonstrating for the first time multiple paternity for this species. We also reported a high paternal skew (10 : 1 in Litter 1 and 7 : 1 in Litter 3), which may be because of post-copulatory or post-zygotic selection processes. These results contribute to a better understanding of the reproductive behaviour of the bull shark, which remains poorly documented. The present study must be expanded to assess the frequency of multiple paternity in this species, and to test for genetic or cryptic benefits (convenience polyandry), which is important for long-term conservation and management plans.
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Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1323-1650 ISBN Médium
Région Expédition Conférence
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Numéro d'Appel MARBEC @ alain.herve @ collection 2073
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Auteur (down) Pirog, A.; Jaquemet, S.; Blaison, A.; Soria, M.; Magalon, H.
Titre Isolation and characterization of eight microsatellite loci from Galeocerdo cuvier (tiger shark) and cross-amplification in Carcharhinus leucas, Carcharhinus brevipinna, Carcharhinus plumbeus and Sphyrna lewini Type Article scientifique
Année 2016 Publication Revue Abrégée PeerJ
Volume 4 Numéro Pages e2041
Mots-Clés age; bull; Carcharhiniform; Control region; growth; hawaiian waters; markers; microsatellites; movements; patterns; Population Genetics; software; western north-atlantic
Résumé The tiger shark Galeocerdo cuvier (Carcharhinidae) is a large elasmobranch suspected to have, as other apex predators, a keystone function in marine ecosystems and is currently considered Near Threatened (Red list IUCN). Knowledge on its ecology, which is crucial to design proper conservation and management plans, is very scarce. Here we describe the isolation of eight polymorphic microsatellite loci using 454 GS-FLX Titanium pyrosequencing of enriched DNA libraries. Their characteristics were tested on a population of tiger shark (n = 101) from Reunion Island (South-Western Indian Ocean). All loci were polymorphic with a number of alleles ranging from two to eight. No null alleles were detected and no linkage disequilibrium was detected after Bonferroni correction. Observed and expected heterozygosities ranged from 0.03 to 0.76 and from 0.03 to 0.77, respectively. No locus deviated from Hardy-Weinberg equilibrium and the global F-IS of the population was of 0.04(NS). Some of the eight loci developed here successfully cross-amplified in the bull shark Carcharhinus leucas (one locus), the spinner shark Carcharhinus brevi pi n n a (four loci), the sandbar shark Carcharhinus plumbeus (five loci) and the scalloped hammerhead shark Sphyrna lewini (two loci). We also designed primers to amplify and sequence a mitochondrial marker, the control region. We sequenced 862 bp and found a low genetic diversity, with four polymorphic sites, a haplotype diversity of 0.15 and a nucleotide diversity of 2 x 10(-4).
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Editeur Lieu de Publication Éditeur
Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 2167-8359 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1651
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Auteur (down) Pirog, A.; Blaison, A.; Jaquemet, S.; Soria, M.; Magalon, H.
Titre Isolation and characterization of 20 microsatellite markers from Carcharhinus leucas (bull shark) and cross-amplification in Galeocerdo cuvier (tiger shark), Carcharhinus obscurus (dusky shark) and Carcharhinus plumbeus (sandbar shark) Type Article scientifique
Année 2015 Publication Revue Abrégée Conservation Genet Resour
Volume 7 Numéro 1 Pages 121-124
Mots-Clés Animal Anatomy / Morphology / Histology; Bull shark; Carcharhinus leucas; Carcharhinus obscurus; Carcharhinus plumbeus; Conservation Biology/Ecology; Evolutionary Biology; Galeocerdo cuvier; Microsatellite; Plant Sciences
Résumé With the development of genetics methods, it becomes possible to study the population structure and some aspects of the reproductive behaviour of endangered sharks. Here we describe the isolation of 20 polymorphic microsatellite markers in the bull shark Carcharhinus leucas (Carcharhinidae) and their characteristics. Two to 10 alleles per locus were detected. Observed and expected heterozygosities ranged from 0.00 to 0.78 and from 0.05 to 0.80, respectively. Four markers showed deviations from Hardy–Weinberg equilibrium; among them, three showed presence of null alleles. No linkage disequilibrium was detected among any of the loci. Moreover, four, 11 and 19 of these 20 markers successfully cross-amplified in the tiger shark Galeocerdo cuvier, the sandbar shark Carcharhinus plumbeus and the dusky shark Carcharhinus obscurus, respectively.
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Editeur Lieu de Publication Éditeur
Langue en Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1877-7252, 1877-7260 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1260
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