Éditeur(s) : HAL CCSD SpringerLink
Résumé : Trinucleotide microsatellites have proven to be the markers of choice in human genetic analysis because they are easier to genotype than dinucleotides. Their development can be more time-consuming due to their lower abundance in the genome. We isolated trinucleotide microsatellites in Norway spruce (Picea abies K.) using an enrichment procedure for the genomic-library construction. Here we report on the characterisation of 85 ATC microsatellite-containing clones, from which 39 markers were developed. Many of the clones showed the occurrence of tandem repeats of higher order than the trinucleotide ones, often resembling minisatellite repeats. The sequencing of a sample of the alleles at one of the loci revealed size homoplasy due to base substitutions within the microsatellite region. The presence of ATC motifs within repetitive sequence families was observed. We found a significant relationship between the level of polymorphism and the length of the microsatellite. The levels of variability for ATC trinucleotide markers were lower than those for dinucleotides, both when tested on all loci in a set of six individuals and on a subset of loci in four natural populations. This difference is most likely attributable to lower mutation rates for trinucleotide than for dinucleotide loci. The availability of markers with different mutation rates allows one to select the proper marker set to investigate population processes on different time scales.
Theoretical and Applied Genetics

hal-01032029
https://hal.archives-ouvertes.fr/hal-01032029
DOI : 10.1007/s00122-002-0986-1

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : Climate models for the coming century predict rainfall reduction in the Amazonian region, including change in water availability for tropical rainforests. Here, we test the extent to which climate variables related to water regime, temperature and irradiance shape the growth trajectories of neotropical trees. . We developed a diameter growth model explicitly designed to work with asynchronous climate and growth data. Growth trajectories of 205 individual trees from 54 neotropical species censused every 2 months over a 4-year period were used to rank 9 climate variables and find the best predictive model. . About 9% of the individual variation in tree growth was imputable to the seasonal variation of climate. Relative extractable water was the main predictor and alone explained more than 60% of the climate effect on tree growth, i.e. 5.4% of the individual variation in tree growth. Furthermore, the global annual tree growth was more dependent on the diameter increment at the onset of the rain season than on the duration of dry season. . The best predictive model included 3 climate variables: relative extractable water, minimum temperature and irradiance. The root mean squared error of prediction (0.035 mm.d(-1)) was slightly above the mean value of the growth (0.026 mm.d(-1)). . Amongst climate variables, we highlight the predominant role of water availability in determining seasonal variation in tree growth of neotropical forest trees and the need to include these relationships in forest simulators to test, in silico, the impact of different climate scenarios on the future dynamics of the rainforest.
ISSN: 1932-6203

hal-01268350
https://hal.archives-ouvertes.fr/hal-01268350
DOI : 10.1371/journal.pone.0034074
PRODINRA : 215438
PUBMED : 22506012

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
High-grade migmatitic and mylonitic gneisses from the Day Nui Con Voi massif in northern Vietnam record temperatures of 760-810 °C at pressures of 6-10 kbars. High temperature conditions have resulted in the development of major element diffusional profiles in garnet. Laser ablation ICP-MS analyses of trace elements indicate that REE and Hf closely followed Rayleigh-like fractionation trends but underwent significant post-crystallization modification. Light REE and to a lesser extent, HREE rim-to-rim zonation profiles show progressive flattening with the decreasing garnet size. Nd and Sm are completely homogenized in the crystals smaller than 1.5 mm, while Lu always preserves variable degrees of core-to-rim concentration gradient. The observed REE patterns are interpreted as resulting from the combination of protracted garnet growth of progressively smaller crystals and intracrystalline diffusion. This had profound influence on Sm-Nd geochronology and resulted in isochron ages ranging from 50 to 32 Ma. The youngest age was obtained for a sample, where all garnet crystals are smaller than 2 mm in which light REE profiles are completely or nearly completely homogenized. Thus, only the youngest age represents geologically meaningful event, and 31.7 ± 0.9 Ma age is interpreted as the best estimate of the resetting episode due to high temperature diffusional homogenization of light REE during early Oligocene metamorphism. Older Sm-Nd ages reflect mixed analyses of variably reset individual garnet crystals. Lu-Hf isotopic analyses of bulk garnet fractions, despite yielding high parent/daughter isotopic ratios appeared very scattered and did not allow defining isochron ages. Instead, apparent ages defined by whole rock and individual garnet fractions range from c. 80 to 160 Ma. Very old apparent ages are interpreted as being the consequence of intracrystalline Lu diffusion and preservation of the original Hf distribution, which leads to lower 176Lu/177Hf ratios, and thus steeper (older) isochrons. Back diffusion of Lu during commonly observed resorption played a subordinate role in modifying isotope systematics.
ISSN: 0009-2541

hal-00813949
https://hal.archives-ouvertes.fr/hal-00813949
DOI : 10.1016/j.chemgeo.2012.04.024

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : International audience
The life-history traits and population dynamics of species are increasingly being attributed to the characteristics of their preferred habitats. While coral reef fish are often strongly associated with particular habitats, long-term studies establishing the demographic and life-history consequences of occupying different reef substrata are rare and no studies have monitored individuals in situ over their lifetime and determined the fate of their offspring. Here, we documented a quasi-turnover and local reproductive success for an entire population of orange clownfish (Amphiprion percula) from Kimbe Island, Papua New Guinea, by taking bi-annual samples of DNA over a 10-yr period (2003–2013). We compared demographic and life-history traits of individuals living on two host anemone species, Heteractis magnifica and Stichodactyla gigantea, including female size, adult continued presence (a proxy for relative longevity range), early post-settlement growth, the number of eggs per clutch and ‘local’ reproductive success (defined for each adult as the number of offspring returning to the natal population). Our results indicate that while the relative longevity of adults was similar on both host anemone species, females living in H. magnifica were larger than females in S. gigantea. However, despite females growing larger and producing more eggs on H. magnifica, we found that local reproductive success was significantly higher for clownfish living in S. gigantea. Life-history traits also exhibited local spatial variation, with higher local reproductive success recorded for adults living on S. gigantea on the eastern side of the island. Our findings support a ‘silver-spoon’ hypothesis that predicts individuals that are fortunate enough to recruit into good habitat and location will be rewarded with higher long-term reproductive success and will make a disproportionate contribution to population renewal.
ISSN: 0722-4028

hal-01357939
https://hal-univ-perp.archives-ouvertes.fr/hal-01357939
DOI : 10.1007/s00338-016-1485-1

Éditeur(s) : HAL CCSD Springer Verlag
Résumé : Growth defense tradeoff theory predicts that plants in low-resource habitats invest more energy in defense mechanisms against natural enemies than growth, whereas plants in high-resource habitats can afford higher leaf loss rates. A less-studied defense against herbivores involves the synchrony of leaf production, which can be an effective defense strategy if leaf biomass production exceeds the capacity of consumption by insects. The aim of this study was to determine whether leaf synchrony varied across habitats with different available resources and whether insects were able to track young leaf production among tree habitat specialists in a tropical forest of French Guiana. We predicted that high-resource habitats would exhibit more synchrony in leaf production due to the low cost and investment to replace leaf tissue. We also expected closer patterns of leaf synchrony and herbivory within related species, assuming that they shared herbivores. We simultaneously monitored leaf production and herbivory rates of five pairs of tree species, each composed of a specialist of terra firme or white-sand forests within the same lineage. Our prediction was not supported by the strong interaction of habitat and lineage for leaf synchrony within individuals of the same species; although habitat specialists differed in leaf synchrony within four of five lineages, the direction of the effect was variable. All species showed short time lags for the correlation between leaf production and herbivory, suggesting that insects are tightly tracking leaf production, especially for the most synchronous species. Leaf synchrony may provide an important escape defense against herbivores, and its expression appears to be constrained by both evolutionary history and environmental factors.
ISSN: 1385-0237

hal-01204221
https://hal.archives-ouvertes.fr/hal-01204221
DOI : 10.1007/s11258-013-0290-y
PRODINRA : 288500

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé :  
1. Despite considerable interest in the application of plant functional traits to questions of community assembly and ecosystem structure and function, there is no consensus on the appropriateness of sampling designs to obtain plot-level estimates in diverse plant communities. 2. We measured 10 plant functional traits describing leaf and stem morphology and ecophysiology for all trees in nine 1-ha plots in terra firme lowland tropical rain forests of French Guiana (N = 4709). 3.We calculated, by simulation, the mean and variance in trait values for each plot and each trait expected under seven sampling methods and a range of sampling intensities. Simulated sampling methods included a variety of spatial designs, as well as the application of existing data base values to all individuals of a given species. 4. For each trait in each plot, we defined a performance index for each sampling design as the proportion of resampling events that resulted in observed means within 5% of the true plot mean, and observed variance within 20%of the true plot variance. 5. The relative performance of sampling designs was consistent for estimations of means and variances. Data base use had consistently poor performance for most traits across all plots, whereas sampling one individual per species per plot resulted in relatively high performance. We found few differences among different spatial sampling strategies; however, for a given strategy, increased intensity of sampling resulted in markedly improved accuracy in estimates of trait mean and variance. 6. We also calculated the financial cost of each sampling design based on data from our 'every individual per plot' strategy and estimated the sampling and botanical effort required. The relative performance of designs was strongly positively correlated with relative financial cost, suggesting that sampling investment returns are relatively constant. 7. Our results suggest that trait sampling for many objectives in species-rich plant communities may require the considerable effort of sampling at least one individual of each species in each plot, and that investment in complete sampling, though great, may be worthwhile for at least some traits.
Functional Ecology

hal-01032175
https://hal.archives-ouvertes.fr/hal-01032175
DOI : 10.1111/j.1365-2435.2009.01600.x

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
This study addresses the mechanical and chemical behavior of allanite during shear zone formation under high-pressure metamorphism. Understanding physico-chemical processes related to the retention or resetting of Pb isotopes in allanite during geological processes is essential for robust petrochronology. Dating of allanite in meta-granodiorite showing variable amounts of strain (from an undeformed protolith to mylonite) at Monte Mucrone (Sesia Zone, NW Italy) gave surprising results. Based on structural and petrographic observations the shear zones at Mt Mucrone are Alpine, yet allanite located within an eclogite facies mylonite yielded Permian ages (208Pb/232Th average age: 287 ± 7 Ma). These mm-sized allanite grains are rimmed by an aggregate of coarse-grained garnet + phengite, thought to derive from former epidote. These aggregates were immersed in a weak matrix that experienced granular flow, and they were thus chemically and mechanically shielded during Alpine mylonitization. In undeformed samples (8a and 8b), two populations of epidote group minerals were found. Allanite forms either coronas around Permian monazite or individual grains with patchy zoning. Both types yield Permian ages (208Pb/232Th age: 291 ± 5 Ma). On the other hand, grains of REE-rich clinozoisite of Cretaceous age are found in undeformed rocks. These grains appear as small fragments with embayed surface outlines and minute satellites or rims around Permian allanite. These (re)crystallized grains are Sr-rich and show mosaic zoning. These results indicate that allanite crystals retained their chemical and isotopic characteristics, and thus their Permian age, as a result of strong strain partitioning between the epidote group porphyroclasts and the eclogite facies matrix in HP-mylonites. The observed partial mobilization of Pb isotopes, which lead to the Cretaceous-aged rims or grains in undeformed samples was facilitated by (re)crystallization of allanite and not by mere Pb diffusion alone under the HP conditions.
ISSN: 0024-4937

insu-00679730
https://hal-insu.archives-ouvertes.fr/insu-00679730
DOI : 10.1016/j.lithos.2011.01.005

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
A better understanding of the key ecological processes of marine organisms is fundamental to improving design and effective implementation of marine protected areas (MPAs) and marine biodiversity. The movement behavior of coral reef fish is a complex mechanism that is highly linked to species life-history traits, predation risk and food resources. We used passive acoustic telemetry to study monthly, daily and hourly movement patterns and space use in two species, Schoolmaster snapper (Lutjanus apodus) and Stoplight parrotfish (Sparisoma viride). We investigated the spatial overlap between the two species and compared intra-specific spatial overlap between day and night. Presence-absence models showed different diel presence and habitat use patterns between the two species. We constructed a spatial network of the movement patterns, which showed that for both species when fish were detected by the array of receivers most movements were made around the coral reef habitat while occasionally moving to silt habitats. Our results show that most individuals made predictable daily crepuscular migrations between different locations and habitat types, although individual behavioral changes were observed for some individuals across time. Our study also highlights the necessity to consider multiple species during MPA implementation and to take into account the specific biological and ecological traits of each species. The low number of fish detected within the receiver array, as well as the intraspecific variability observed in this study, highlight the need to compare results across species and individuals to be used for MPA management.
ISSN: 0141-1136

hal-01169390
https://hal-univ-perp.archives-ouvertes.fr/hal-01169390
DOI : 10.1016/j.marenvres.2015.06.004

Éditeur(s) : HAL CCSD Wiley
Résumé : [b]1.[/b] Plant functional traits, in particular specific leaf area (SLA), wood density and seed mass, are often good predictors of individual tree growth rates within communities. Individuals and species with high SLA, low wood density and small seeds tend to have faster growth rates.[br/][br/][b]2.[/b] If community-level relationships between traits and growth have general predictive value, then similar relationships should also be observed in analyses that integrate across taxa, biogeographic regions and environments. Such global consistency would imply that traits could serve as valuable proxies for the complex suite of factors that determine growth rate, and, therefore, could underpin a new generation of robust dynamic vegetation models. Alternatively, growth rates may depend more strongly on the local environment or growth–trait relationships may vary along environmental gradients.[br/][br/][b]3.[/b] We tested these alternative hypotheses using data on 27 352 juvenile trees, representing 278 species from 27 sites on all forested continents, and extensive functional trait data, 38% of which were obtained at the same sites at which growth was assessed. Data on potential evapotranspiration (PET), which summarizes the joint ecological effects of temperature and precipitation, were obtained from a global data base.[br/][br/][b]4.[/b] We estimated size-standardized relative height growth rates (SGR) for all species, then related them to functional traits and PET using mixed-effect models for the fastest growing species and for all species together.[br/][br/][b]5.[/b] Both the mean and 95th percentile SGR were more strongly associated with functional traits than with PET. PET was unrelated to SGR at the global scale. SGR increased with increasing SLA and decreased with increasing wood density and seed mass, but these traits explained only 3.1% of the variation in SGR. SGR–trait relationships were consistently weak across families and biogeographic zones, and over a range of tree statures. Thus, the most widely studied functional traits in plant ecology were poor predictors of tree growth over large scales.[br/][br/][b]6.[/b] Synthesis. We conclude that these functional traits alone may be unsuitable for predicting growth of trees over broad scales. Determining the functional traits that predict vital rates under specific environmental conditions may generate more insight than a monolithic global relationship can offer.
ISSN: 0022-0477

hal-01204226
https://hal.archives-ouvertes.fr/hal-01204226
DOI : 10.1111/1365-2745.12401
PRODINRA : 307144

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Most peridotite massifs and mantle xenoliths show a wide range of isotopic variations, often involving significant decoupling between Hf, Nd and Sr isotopes. These variations are generally ascribed either to mingling of individual components of contrasted isotopic compositions or to time integration of parent-element enrichment by percolating melts/fluids, superimposed onto previous depletion event(s). However, strong isotopic decoupling may also arise during porous flow as a result of daughter-elements fractionation during solid-liquid interaction. Although porous flow is recognized as an important process in mantle rocks, its effects on mantle isotopic variability have been barely investigated so far. The peridotites of the Lherz massif (French Pyrenees) display a frozen melt percolation front separating highly refractory harzburgites from refertilized lherzolites. Isotopic signatures observed at the melt percolation front show a strong decoupling of Hf from Nd and Sr isotopes that cannot be accounted for by simple mixing involving the harzburgite protolith and the percolating melt. Using one dimensional percolation-diffusion and percolation-reaction modeling, we show that these signatures represent transient isotopic compositions generated by porous flow. These signatures are governed by a few critical parameters such as daughter element concentrations in melt and peridotite, element diffusivity, and efficiency of isotopic homogenization rather than by the chromatographic effect of melt transport and the refertilization reaction. Subtle variations in these parameters may generate significant inter-isotopic decoupling and wide isotopic variations in mantle rocks. (C) 2009 Elsevier B.V. All rights reserved.
ISSN: 0012-821X

hal-00413135
https://hal.archives-ouvertes.fr/hal-00413135
DOI : 10.1016/j.epsl.2008.12.033

Éditeur(s) : HAL CCSD
Résumé : The relation between primary and secondary growth has been traditionally studied in terms of growth units and has always being assumed as closely correlated. Pluviometric variation directly affects growth patterns in the neotropical pioneer species Jacaranda copaia. In French Guiana this species produces annual growth rings in the dry season that can be seen with the naked eye.The morphological and anatomical description of three monocaulous individuals was made node by node. The trees where felled at a roadside locality close to the city of Kourou, French Guiana. The comparison of intermodal distance, pith transversal area and wood ring area variation within an individual elucidates the origin of well-known problems in dendrochronological analysis of tropical trees.The wood found close to the pith, known as young wood, always has false wood rings; the production of these rings is correlated with short intermodal distances and small pith transversal area. This phenomenon seems to be caused by minor intrannual pluviometric variation that affects both primary and secondary growth. This new methodological approach helps morphologists and anatomists interpret growth patterns in tropical trees in a more holistic way.
Botany 2010
Rhode Island, United States

hal-01032389
https://hal.archives-ouvertes.fr/hal-01032389

Éditeur(s) : HAL CCSD Taylor & Francis
Résumé : International audience
The aim of this study was to examine the influence of exercise intensity and session duration on rating of perceived exertion (RPE) in adolescent Taekwondo (TKD) athletes. Twelve male youth competitive TKD athletes, aged between 13 and 18 years took part in this study. Training data (368 individual sessions) were collected during the 12 weeks of the precompetitive TKD season. Daily training load was calculated using the heart rate and the session-RPE. Exercise intensity was also classified in five zones [i.e. 5060%, 6170%, 7180%, 8190% and 91100% of maximal heart rate (HRmax)] and the time spent in each zone was expressed as percentage of total session time. The analysis of variance showed a significantmain effect for zone (pB0.001) with most of the time (69%) spent at intensities between 61 and 90% of HRmax, and only 10% spent above 91% (mean differences compared to the other zones ranging from 6.6% versus zone 1 to 14.8% versus zone 3; pB0.0001). The individual correlation between session-RPE and HR-based methods were moderate to large. The stepwise multiple regression showed that RPE was influenced mainly by the time spent in the high intensity zone that explained 22.1% of the variance in RPE. Session duration accounted for only an additional 3.2%. The results suggest the time spent at high-intensity (i.e. between 91 and 100% HRmax) and only marginally the session duration influences theRPE referred to the whole training session. This seems to confirm that the determination of the TL multiplying the RPE andsession duration is acceptable.
ISSN: 1746-1391

hal-01163939
https://hal.univ-antilles.fr/hal-01163939
DOI : 10.1080/17461391.2012.691115

Éditeur(s) : HAL CCSD Elsevier
Résumé :  
Tree species-rich tropical rainforests are characterized by a highly variable quality of leaf litter input to the soil at small spatial scales. This diverse plant litter is a major source of energy and nutrients for soil microorganisms, particularly in rainforests developed on old and nutrient-impoverished soils. Here we tested the hypothesis that the variability in leaf litter quality produced by a highly diverse tree community determines the spatial variability of the microbial respiration process in the underlying soil. We analyzed a total of 225 litter-soil pairs from an undisturbed Amazonian rainforest in French Guiana using a hierarchical sampling design. The microbial respiration process was assessed using substrateinduced respiration (SIR) and compared to a wide range of quality parameters of the associated litter layer (litter nutrients, carbon forms, stoichiometry, litter mass and pH). The results show that the variability of both litter quality and SIR rates was more important at large than at small scales. SIR rates varied between 1.1 and 4.0 mg g_1 h_1 and were significantly correlated with litter layer quality (up to 50% of the variability explained by the best mixed linear model). Total litter P content was the individual most important factor explaining the observed spatial variation in soil SIR, with higher rates associated to high litter P. SIR rates also correlated positively with total litter N content and with increasing proportions of labile C compounds. However, contrary to our expectation, SIR rates were not related to litter stoichiometry. These data suggest that in the studied Amazonian rainforest, tree canopy composition is an important driver of the microbial respiration process via leaf litter fall, resulting in potentially strong plant-soil feedbacks. .
ISSN: 0038-0717

hal-01032139
https://hal.archives-ouvertes.fr/hal-01032139
DOI : 10.1016/j.soilbio.2011.01.018

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : International audience
A decreased global autonomic nervous system (ANS) activity and increased sympathetic activation in patients with sickle cell anemia (SCA) seem to worsen the clinical severity and could play a role in the pathophysiology of the disease, notably by triggering vaso-occlusive crises. Because exercise challenges the ANS activity in the general population, we sought to determine whether a short (,15 min) and progressive moderate exercise session conducted until the first ventilatory threshold had an effect on the ANS activity of a group of SCA patients and a group of healthy individuals (CONT group). Temporal and spectral analyses of the nocturnal heart rate variability were performed before and on the 3 nights following the exercise session. Standard deviation of all normal RR intervals (SDNN), total power, low frequencies (LF) and high frequencies powers (HF) were lower but LF/HF was higher in SCA patients than in the CONT group. Moderate exercise did not modify ANS activity in both groups. In addition, no adverse clinical events occurred during the entire protocol. These results imply that this kind of short and moderate exercise is not detrimental for SCA patients.
ISSN: 1932-6203

hal-01136725
https://hal.univ-antilles.fr/hal-01136725
https://hal.univ-antilles.fr/hal-01136725/document
https://hal.univ-antilles.fr/hal-01136725/file/Hedreville%20et%20al.%20-%202014%20-%20Acute%20moderate%20exercise%20does%20not%20further%20alter%20the%20autonomic%20nervous%20system%20activity%20in%20patients%20with%20sick%282%29.pdf
DOI : 10.1371/journal.pone.0095563

Éditeur(s) : Université de la Réunion
Résumé : The green turtle (Chelonia mydas) is an emblematic species of marine life. However, nowadays it is subject to many threats (poaching, by-catch). Even if there is deep growing measures for its protection, the green turtle still is an endangered species and it is listed in Appendix I of Washington Convention (CITES). In order to elaborate efficient conservation and management plans, perfect knowledge of green turtle biology, but also of its population structure and their characteristics, are needed. In this thesis, we have assessed genetic structure of green turtle populations in the South-Western Indian Ocean by using genetic tools. In all, 1551 tissue samples have been collected from our study zone and from our control site French Polynesia (37 samples). All kinds if individuals were sampled (except males in reproductive phase) from 15 sampling sites including nesting, foraging, and immature development site. We used both control region of mitochondrial DNA and 6 microsatellite loci to better infer maternal and paternal lineages. We identified 29 haplotypes in the South-Western Indian Ocean. They are distributed in 3 independent and highly divergent clades, including one composed with haplotypes from Atlantic Ocean. For 7 of these haplotypes, it was the first time they were detected in the study zone. Fifteen haplotypes were previously undescribed, distributed in all the 3 clades. These new haplotypes seem to be specific to the South-Western Indian Ocean, which is then an original zone. Besides, we found a high allelic richness. These results show the South-western Indian Ocean is rich and very diversified. This region plays an important role in the global diversity of the species. The South-Western Indian Ocean is one of the two contact zones presently known between the two metapopulations of green turtles (Atlantic-Mediterranean and Indo-Pacific). This contact induces a genetic cline based on CM8 (Atlantic) and C3 (Indo-Pacific) haplotype frequencies. Analysis of the microsatellite differentiation between individuals provides evidence of genetic exchanges between the two metapopulations in the region. The South-Western Indian Ocean participates to green turtle global genetic mixing. Studying the influence of several intrinsic and extrinsic factors on population structuring provides useful information for management plan elaboration. We found no significant difference between genetic structures of foraging females and males, contrary to immature turtles which seem to be organised in 'regional pools'. This organisation could be due to both immature natal homing and influence of oceanic currents. High mitochondrial differentiation of nesting females and low global microsatellite differentiation of our samples indicate male-mediated gene flow among populations of the study zone. The genetic composition of a sampling site presents no significant variation along the year, even if we could notice some trends. Nevertheless, it can be significantly different from a year to an other one. This may result from alternation of distinct populations on the same site. We noticed different evolution in 10 or 20 years of the genetic composition depending on the sampling site. Geographic distance seems not to have significant influence on population structuring concerning microsatellite markers. Nesting females of Saziley Beach (Mayotte Island, Comoros Archipelago) present genetic divergence from females nesting in the two other sampled beaches of this island. The observed population structure shows no contradiction with the organisation of oceanic currents in the South-Western Indian Ocean. Comparing the results from the two genetic markers used, we identified 8 genetic differentiated clusters of turtles in the study zone and at least 6 distinct populations. These clusters constitute 8 potential management units (MUs) which could serve as basis in the elaboration of conservation and management plans.
La tortue verte (Chelonia mydas) constitue l'un des espèces emblématiques de la vie marine, pourtant de nombreuses menaces pèsent de nos jours encore sur sa survie (braconnage, captures accidentelles). Ainsi, malgré l'essor de mesures de protection menées à travers pour sa sauvegarde, la tortue verte constitue une espèce 'en danger d'extinction' et figure dans l'Annexe I de la Convention de Washington (CITES). Afin d'élaborer des plans de gestion et de conservation qui soient efficaces, il est important d'avoir une parfaite connaissance de la biologie de la tortue verte, mais aussi de la structure de ses populations et de leurs caractéristiques. C'est dans ce cadre que s'inscrit la présente étude. L'objectif de cette étude était d'acquérir des connaissances sur la structure des populations de tortues vertes dans le sud-ouest de l'océan Indien grâce à l'utilisation de l'outil génétique. Au total, 1551 échantillons de tissu ont été collectés dans la zone d'étude et dans notre site témoin la Polynésie française (37 échantillons). Toutes les catégories d'individus ont été échantillonnées (excepté les mâles en phase de reproduction) et les 15 sites d'échantillonnage comprennent à la fois des sites de ponte, d'alimentation et de développement pour les immatures. Deux types de marqueurs ont été utilisés : la région contrôle de l'ADN mitochondrial et 6 loci microsatellites, afin d'appréhender au mieux l'apport des lignées maternelles et paternelles. Nous avons pu mettre en évidence la présence dans le sud-ouest de l'océan Indien de 29 haplotypes distincts, appartenant à trois clades fortement divergents dont l'un constitué d'haplotypes originaires de l'océan Atlantique. Parmi ces haplotypes, 7 ont été détectés pour la première fois dans la zone d'étude, et 15 autres n'ont jamais été précédemment décrits chez cette espèce. Ils sont présents dans chacun des 3 clades d'haplotypes. Ces nouveaux haplotypes semblent spécifiques à la région, et en font une zone originale. On observe par ailleurs une grande richesse allélique dans les effectifs analysés. Ces résultats montrent que le sud-ouest de l'océan Indien est une zone riche et très diversifiée. Cette région joue un rôle important dans la diversité génétique globale de l'espèce. Le sud-ouest de l'océan Indien constitue l'une des deux seules zones connues à l'heure actuelle de contact entre les deux métapopulations de tortues vertes (Atlantique-Méditerranée et Indo-Pacifique). Ce contact a entraîné la formation d'un cline génétique portant principalement sur les fréquences relatives des haplotypes CM8 (Atlantique) et C3 (Indo-Pacifique). Les résultats obtenus lors de l'analyse microsatellite de la différenciation entre les individus originaires des deux métapopulations montrent que le sud-ouest de l'océan Indien constitue une zone d'échanges génétiques entre les deux métapopulations, participant au brasage génétique de l'espèce. L'étude de facteurs, intrinsèques et extrinsèques, pouvant influencer la structuration des populations apportent de nombreuses informations qui pourraient s'avérer utiles lors de l'élaboration de plans de gestion. La structure des femelles et des mâles en alimentation ne diffère pas, contrairement à celle des immatures qui semble s'organiser en 'pools régionaux' qui seraient le fruit de l'interaction d'un comportement de philopatrie et d'une influence des courants océaniques. La forte différenciation mitochondriale des femelles en ponte et la très faible différenciation microsatellite observée à l'échelle de la région, indiquent l'existence de flux de gènes via les mâles. La composition génétique d'un site ne varie pas de manière significative au cours de l'année. Par contre, elle peut varier d'une année à l'autre, signifiant l'alternance dans certains sites de ponte de plusieurs populations distinctes. L'évolution de la composition génétique d'un groupe, au cours de 10 ou 20 ans, diffère selon le site considéré. La distance ne semble pas influencer de manière significative la structuration des populations au niveau microsatellite. Les femelles en ponte sur la plage de Saziley (Mayotte) diffèrent génétiquement de celles pondant sur les deux autres plages de l'île. La structure observée des populations est en accord avec l'organisation des courants océanique dans la région. La confrontation des résultats obtenus à partir des deux marqueurs génétiques utilisés, permet la détermination de 8 ensembles génétiquement différenciés dans la zone d'étude et l'identification d'au moins 6 populations distinctes. Ces ensembles constituent autant d'unités de gestion (MUs) potentielles qui pourront servir de base à l'élaboration de plans de gestion et de conservation.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/2007/these-3532.pdf
http://archimer.ifremer.fr/doc/00000/3532/

Éditeur(s) : HAL CCSD
Résumé : In a recent study based on a retrospective reconstruction of growth, we showed for Cecropia sciadophylla that branching and flowering processes, as well as alternation of long and short nodes were regularly spaced by ~23 nodes. We also found that this strong periodicity was related to an annual cycle of growth. Adult trees are successful individuals that have reached the canopy and our previous results were found in adult trees, suggesting that variability in the number of nodes produced per year is underestimated, because the degree of variation decreases with age. Here, we hypothesized that growth periodicity could be related to rainfall and we focus on two C. sciadophylla populations with contrasting precipitation seasonality. During 19 months and for 69 saplings, we measured growth at regular monthly intervals to test the intra-annual variability in the number of nodes produced per month and per year. We also characterized the intra-annual fluctuations in the number of present leaves in the main axis and internode lengths among months. We found that node elongation and number of present leaves in the main axis vary among months in the population subjected to a strong seasonal precipitation. In contrast, the population subjected to a non-seasonal precipitation showed smaller variation in node elongation and no variation in the number of leaves presented in the main axis among months. Regardless the population of origin, we also found that ~23 was the number of nodes produced per year and that the time required to produce a new node was ~15 days at any month of the year. The strong stability in the average number of nodes produced per month and per year among populations, suggests a genetically controlled trait. In spite of a strong genetic determination on the number of nodes produced per year, several environmental factors, including rainfall, could be the cause of the observed variation in elongation and number of present leaves in the main axis.INRAUM2
Botany 2010
Rhode Island, United States

hal-01191343
https://hal.archives-ouvertes.fr/hal-01191343
PRODINRA : 178581

Éditeur(s) : Institut national agronomique Paris Grignon
Résumé : The flat oyster Ostrea edulis L. is the indigenous oyster of the Atlantic as well as the Mediterranean coasts of Europe. Its commercial exploitation dates back to Antiquity but its breeding is now threatened by two parasitic protozoa, among which Bonamia ostreae. Various aspects of the genetics of this species' natural and farmed populations have been studied with the aid of microsatellite markers. At first, the implementation and the screening of two partial genomic libraries made it possible to identify 28 new microsatellite loci. Analysis of the segregation of 12 of these loci and of two enzymatic loci shows that most microsatellite loci are transmitted in a Mendelian way, but some loci have significant segregation distortions. Moreover, seven linkage groups, of which four contain at least two markers, were identified in Ostrea edulis. The genetic variability of three populations selected for one or two generations for resistance to Bonamia ostreae was analysed with the aid of 5 microsatellite loci. In spite of the absence of genealogical data, we have shown that these selected populations were descended from a very low number of founding genitors (from 3 to 15 depending on the population) and for two populations, we were able to reconstruct the genealogy and the relationships between the individuals were identified. These selected populations have, in addition to a very low genetic variability, real and at times high levels of consanguinity. These results have a significant implication for the continuation of the selection programme (consanguinity management, augmentation of genetic variability by introducing wild genitors). The geographical structuring of the genetic variability of natural populations of Ostrea edulis has been analysed with the aid of 5 microsatellite loci on a sampling covering almost the entire distribution area of the species (from Norway to the Adriatic Sea). The results are consistent with those published in the literature and using enzymatic markers. The populations show a low level of differentiation that could correspond to a model of isolation by distance. The Atlantic populations, which have a reduced polymorphism, could be descended from post-glacial recolonisation from Mediterranean populations that had survived the glaciations of the Quaternary Period. The current distribution of flat oyster populations is surely also subject to anthropogenic activities. Finally, the genetic bases of the heterozygosis-growth correlation were studied in a natural population with the aid of enzymatic and microsatellite markers. Although leads favouring the direct contribution of enzymatic loci have been found, biases in the sampling design make it impossible to come to a formal conclusion. However, this study has made it possible to show that the capture of individuals over a short period (around ten days) leads to a sampling of a population descended from a very low number of founding genitors, in contradiction with the generally accepted idea that marine bivalve populations are large panmictic populations with significant, efficient numbers. These results confirm in a natural population the observations of a significant reduction of efficient sizes in hatchery populations.
L'huître plate Ostrea edulis L. est l'huître indigène des côtes européennes aussi bien atlantiques que méditerranéennes. Son exploitation commerciale remonte à l'Antiquité mais son élevage est aujourd'hui menacé par deux protozoaires parasites dont Bonamia ostreae. Différents aspects de la génétique des populations naturelles et cultivées de cette espèce ont été étudiés à l'aide de marqueurs microsatellites. Dans un premier temps, la réalisation et le criblage de deux banques génomiques partielles ont permis l'identification de 28 nouveaux locus microsatellites. L'analyse de la ségrégation de 12 de ces locus et de deux locus enzymatiques montre que la plupart des locus microsatellites sont transmis de façon mendélienne, mais certains locus présentent des distorsions de ségrégation importantes. Par ailleurs, sept groupes de liaison dont quatre contiennent au moins deux marqueurs ont été identifiés chez Ostrea edulis. La variabilité génétique de trois populations sélectionnées depuis une ou deux générations pour une résistance à Bonamia ostreae a été analysée à l'aide de 5 locus microsatellites. Malgré l'absence de données généalogiques, nous avons montré que ces populations sélectionnées étaient issues d'un très faible nombre de géniteurs fondateurs (de 3 à 15 selon les populations) et pour deux populations, la généalogie a pu être reconstituée et les liens de parenté entre les individus ont été identifiés. Ces populations sélectionnées présentent, outre une très faible variabilité génétique, des niveaux de consanguinité réels et parfois élevés. Ces résultats ont une implication importante pour la continuation du programme de sélection (gestion de la consanguinité, augmentation de la variabilité génétique par introduction de géniteurs sauvages). La structuration géographique de la variabilité génétique des populations naturelles d'Ostrea edulis a été analysée à l'aide de 5 locus microsatellites sur un échantillonnage couvrant presque toute l'aire de répartition de l'espèce (de la Norvège à la Mer Adriatique). Les résultats sont cohérents avec ceux publiés dans la littérature et utilisant des marqueurs enzymatiques. Les populations montrent un niveau de différenciation faible qui pourrait correspondre à un modèle d'isolement par la distance. Les populations atlantiques, qui présentent un polymorphisme réduit, pourraient être issues de recolonisation post-glaciaire à partir de populations méditerranéennes ayant survécu aux glaciations du Quaternaire. La répartition actuelle des populations d'huître plate est certainement aussi soumise aux actions anthropiques. Enfin, les bases génétiques de la corrélation hétérozygotie-croissance ont été étudiées dans une population naturelle à l'aide de marqueurs enzymatiques et microsatellites. Bien que des pistes en faveur de la contribution directe des locus enzymatiques aient été trouvées, des biais dans le dispositif expérimental ne permettent pas de conclure de façon formelle. Cependant, cette étude a permis de montrer que le captage d'individus sur une faible période (une dizaine de jours) conduit à l'échantillonnage d'une population issue d'un nombre très réduit de géniteurs fondateurs, en contradiction avec l'idée reçue que les populations de bivalves marins sont de larges populations panmictiques à effectif efficace important. Ces résultats confirment dans une population naturelle les observations de réduction importante des tailles efficaces dans des populations d'écloserie.

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1998/these-1919.pdf
http://archimer.ifremer.fr/doc/00000/1919/

Éditeur(s) : HAL CCSD Oxford University Press (OUP): Policy P - Oxford Open Option A Oxford University Press (OUP)
Résumé : International audience
The Pyrenean mountain range is a slowly deforming belt with continuous and moderate seismic activity. To quantify its deformation field, we present the velocity field estimated from a GPS survey of the Pyrenees spanning 18 yr. The PotSis and ResPyr networks, including a total of 85 GPS sites, were installed and first measured in 1992 and 1995–1997, respectively, and remeasured in 2008 and 2010. We obtain a deformation field with velocities less than 1 mm yr−1 across the range. The estimated velocities for individual stations do not differ significantly from zero with 95 per cent confidence. Even so, we estimate a maximum extensional horizontal strain rate of 2.0 ± 1.7 nanostrain per year in a N–S direction in the western part of the range. We do not interpret the vertical displacements due to their large uncertainties. In order to compare the horizontal strain rates with the seismic activity, we analyse a set of 194 focal mechanisms using three methods: (i) the ‘r’ factor relating their P and T axes, (ii) the stress tensors obtained by fault slip inversion and (iii) the strain-rate tensors. Stress and strain-rate tensors are estimated for: (i) the whole data set, (ii) the eastern and western parts of the range separately, and (iii) eight zones, which are defined based on the seismicity and the tectonic patterns of the Pyrenees. Each of these analyses reveals a lateral variation of the deformation style from compression and extension in the east to extension and strike-slip in the west of the range. Although the horizontal components of the strain-rate tensors estimated from the seismic data are slightly smaller in magnitude than those computed from the GPS velocity field, they are consistent within the 2σ uncertainties. Furthermore, the orientations of their principal axes agree with the mapped active faults.
ISSN: 0956-540X

hal-01171752
https://hal.archives-ouvertes.fr/hal-01171752
DOI : 10.1093/gji/ggv052

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
The shallow-water bivalve Codakia orbiculata which harbors gill-endosymbiotic sulfur-oxidizing ?-proteobacteria can lose and acquire its endosymbionts throughout its life. Long-term starvation and recolonization experiments led to changes in the organization of cells in the lateral zone of gill filaments. This plasticity is linked to the presence or absence of gill-endosymbionts. Herein, we propose that this reorganization can be explained by three hypotheses: (a) a variation in the number of bacteriocytes and granule cells due to proliferation or apoptosis processes, (b) a variation of the volume of these two cell types without modification in the number, and (c) a combination of both number and cell volume variation. To test these hypotheses, we analyzed cell reorganization in terms of proliferation and apoptosis in adults submitted to starvation and returned to the field using catalyzed reporter deposition fluorescence in situ hybridization, immunohistochemistry, and structural analyses. We observed that cell and tissue reorganization in gills filaments is due to a variation in cell relative abundance that maybe associated with a variation in cell apparent volume and depends on the environment. In fact, bacteriocytes mostly multiply in freshly collected and newly recolonized individuals, and excess bacteriocytes are eliminated in later recolonization stages. We highlight that host tissue regeneration in gill filaments of this symbiotic bivalve can occur by both replication of existing cells and division of undifferentiated cells localized in tissular bridges, which might be a tissue-specific multipotent stem cell zone.
ISSN: 1059-910X

hal-01545915
https://hal.archives-ouvertes.fr/hal-01545915
DOI : 10.1002/jemt.22041

Éditeur(s) : HAL CCSD Wiley
Résumé : International audience
BACKGROUND: An association between education and preterm delivery has been observed in populations across Europe, but differences in methodology limit comparability. We performed a direct cross-cohort comparison of educational disparities in preterm delivery based on individual-level birth cohort data. METHODS: The study included data from 12 European cohorts from Denmark, England, France, Lithuania, the Netherlands, Norway, Italy, Portugal, and Spain. The cohorts included between 2434 and 99 655 pregnancies. The association between maternal education and preterm delivery (22-36 completed weeks of gestation) was reported as risk ratios, risk differences, and slope indexes of inequality with 95% confidence intervals (CIs). RESULTS: Singleton preterm live delivery proportion varied between 3.7% and 7.5%. There were large variations between the cohorts in the distribution of education and maternal characteristics. Nevertheless, there were similar educational differences in risk of preterm delivery in 8 of the 12 cohorts with slope index of inequality varying between 2.2 [95% CI 1.1, 3.3] and 4.0 [95% CI 1.4, 6.6] excess preterm deliveries per 100 singleton deliveries among the educationally most disadvantaged, and risk ratio between the lowest and highest education category varying from 1.4 [95% CI 1.1, 1.8] to 1.9 [95% CI 1.2, 3.1]. No associations were found in the last four cohorts. CONCLUSIONS: Educational disparities in preterm delivery were found all over Europe. Despite differences in the distributions of education and preterm delivery, the results were remarkably similar across the cohorts. For those few cohorts that did not follow the pattern, study and country characteristics did not explain the differences.
ISSN: 0269-5022

hal-01146842
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01146842
DOI : 10.1111/ppe.12185
PUBMED : 25808200