Molecular and Quantitative Genetic Differentiation in European Populations of Silene latifolia (Caryophyllaceae)

Background and Aims Among-population differentiation in phenotypic traits and allelic variation is expected as a consequence of isolation, drift, founder effects and local selection. Therefore, investigating molecular and quantitative genetic divergence is a pre-requisite for studies of local adaptation in response to selection under variable environmental conditions. Methods Among- and within-population variation were investigated in six geographically separated European populations of the white campion, Silene latifolia, both for molecular variation at six newly developed microsatellite loci and for quantitative variation in morphological and life-history traits. To avoid confounding effects of the maternal environment, phenotypic traits were measured on greenhouse-reared F1 offspring. Tests were made for clinal variation, and the correlations among molecular, geographic and phenotypic distances were compared with Mantel tests. Key Results The six populations of Silene latifolia investigated showed significant molecular and quantitative genetic differentiation. Geographic and phenotypic distances were significantly associated. Age at first flowering increased significantly with latitude and exhibited a Qst value of 0·17 in females and 0·10 in males, consistent with adaptation to local environmental conditions. By contrast, no evidence of isolation-by-distance and no significant association between molecular and phenotypic distances were found. Conclusions Significant molecular genetic divergence among populations of Silene latifolia, from the European native range is consistent with known limited seed and pollen flow distances, while significant quantitative genetic divergence among populations and clinal variation for age at first flowering suggest local adaptatio

Les documents scientifiques informels: un patrimoine peu exploré, témoin de la construction des savoirs

L'objectif du projet ECRITO était de contribuer à préserver et à valoriser les documents scientifiques produits quotidiennement par les chercheurs de Midi-Pyrénées, en amont des publications formelles : non seulement les articles, communications ou monographies, qui constituent la partie visible de la recherche, mais aussi tous les matériaux et informations accumulés par les chercheurs, et sur la base desquels se construit leur travail. Ces matériaux sont de types très divers : littérature " grise " (rapports, mémoires, documentation techniques...), documents textuels " informels " (carnets, notes, brouillons, correspondances, cahiers de laboratoires), corpus visuels, sonores ou multimédia (campagnes photographiques, campagnes d'enquêtes, enregistrements audio ou vidéo), données électroniques (bases de données, fichiers informatiques), etc. Le projet visait également à prolonger, de manière exploratoire, le questionnement sur le patrimoine scientifique à partir des traces matérielles produites quotidiennement par les chercheurs dans leurs activités de recherche. Ces traces représentent en effet une fenêtre irremplaçable sur la science en train de se construire : elles permettent de rendre visible et compréhensible le processus habituellement dissimulé de production de la science, ce qui constitue un enjeu scientifique et pédagogique fondamental

Anthropogenic boat noise reduces feeding success in winter flounder larvae (Pseudopleuronectes americanus)

The aim of this study was to explore an emerging discipline addressing the impact of anthropogenic noise on larval stages of marine organisms. We assessed the influence of boat noise on the feeding behaviour of the pelagic larvae of winter flounder (Pseudopleuronectes americanus, Walbaum, 1792). The hypothesis was that boat noise influences the feeding behaviour of P. americanus flounder larvae independently of prey density. Aquaria containing P. americanus larvae were placed in water baths in which boat noise was diffused for the “noise” treatment and compared to control aquaria with no sound emissions. Larvae were filmed using cameras placed above the aquaria and their behaviour was recorded. Larvae exposed to anthropogenic noise displayed significantly fewer hunting events than controls, and their stomach volumes were significantly smaller. This noise effect was the same at all prey densities used, suggesting that larval feeding behaviour is negatively impaired by anthropogenic noise. Keywords : Feeding behaviour ; Winter flounder ; Larvae ; Anthropogenic noise ; Vessel noise

Revealing hidden species diversity in closely related species using nuclear SNPs, SSRs and DNA sequences - a case study in the tree genus Milicia

Background: Species delimitation in closely related plant taxa can be challenging because (i) reproductive barriers are not always congruent with morphological differentiation, (ii) use of plastid sequences might lead to misinterpretation, (iii) rare species might not be sampled. We revisited molecular-based species delimitation in the African genus Milicia, currently divided into M. regia (West Africa) and M. excelsa (from West to East Africa). We used 435 samples collected in West, Central and East Africa. We genotyped SNP and SSR loci to identify genetic clusters, and sequenced two plastid regions (psbA-trnH, trnC-ycf6) and a nuclear gene (At103) to confirm species’ divergence and compare species delimitation methods. We also examined whether ecological niche differentiation was congruent with sampled genetic structure. Results: West African M. regia, West African and East African M. excelsa samples constituted three well distinct genetic clusters according to SNPs and SSRs. In Central Africa, two genetic clusters were consistently inferred by both types of markers, while a few scattered samples, sympatric with the preceding clusters but exhibiting leaf traits of M. regia, were grouped with the West African M. regia cluster based on SNPs or formed a distinct cluster based on SSRs. SSR results were confirmed by sequence data from the nuclear region At103 which revealed three distinct ‘Fields For Recombination’ corresponding to (i) West African M. regia, (ii) Central African samples with leaf traits of M. regia, and (iii) all M. excelsa samples. None of the plastid sequences provide indication of distinct clades of the three species-like units. Niche modelling techniques yielded a significant correlation between niche overlap and genetic distance. Conclusions: Our genetic data suggest that three species of Milicia could be recognized. It is surprising that the occurrence of two species in Central Africa was not reported for this well-known timber tree. Globally, our work highlights the importance of collecting samples in a systematic way and the need for combining different nuclear markers when dealing with species complexes. Recognizing cryptic species is particularly crucial for economically exploited species because some hidden taxa might actually be endangered as they are merged with more abundant species

Rapid response to the M_w 4.9 earthquake of November 11, 2019 in Le Teil, Lower Rhône Valley, France

On November 11, 2019, a Mw 4.9 earthquake hit the region close to Montelimar (lower Rhône Valley, France), on the eastern margin of the Massif Central close to the external part of the Alps. Occuring in a moderate seismicity area, this earthquake is remarkable for its very shallow focal depth (between 1 and 3 km), its magnitude, and the moderate to large damages it produced in several villages. InSAR interferograms indicated a shallow rupture about 4 km long reaching the surface and the reactivation of the ancient NE-SW La Rouviere normal fault in reverse faulting in agreement with the present-day E-W compressional tectonics. The peculiarity of this earthquake together with a poor coverage of the epicentral region by permanent seismological and geodetic stations triggered the mobilisation of the French post-seismic unit and the broad French scientific community from various institutions, with the deployment of geophysical instruments (seismological and geodesic stations), geological field surveys, and field evaluation of the intensity of the earthquake. Within 7 days after the mainshock, 47 seismological stations were deployed in the epicentral area to improve the Le Teil aftershocks locations relative to the French permanent seismological network (RESIF), monitor the temporal and spatial evolution of microearthquakes close to the fault plane and temporal evolution of the seismic response of 3 damaged historical buildings, and to study suspected site effects and their influence in the distribution of seismic damage. This seismological dataset, completed by data owned by different institutions, was integrated in a homogeneous archive and distributed through FDSN web services by the RESIF data center. This dataset, together with observations of surface rupture evidences, geologic, geodetic and satellite data, will help to unravel the causes and rupture mechanism of this earthquake, and contribute to account in seismic hazard assessment for earthquakes along the major regional Cévenne fault system in a context of present-day compressional tectonics

Molecular and Quantitative Genetic Differentiation in European Populations of Silene latifolia (Caryophyllaceae)

BACKGROUND AND AIMS: Among-population differentiation in phenotypic traits and allelic variation is expected as a consequence of isolation, drift, founder effects and local selection. Therefore, investigating molecular and quantitative genetic divergence is a pre-requisite for studies of local adaptation in response to selection under variable environmental conditions. METHODS: Among- and within-population variation were investigated in six geographically separated European populations of the white campion, Silene latifolia, both for molecular variation at six newly developed microsatellite loci and for quantitative variation in morphological and life-history traits. To avoid confounding effects of the maternal environment, phenotypic traits were measured on greenhouse-reared F(1) offspring. Tests were made for clinal variation, and the correlations among molecular, geographic and phenotypic distances were compared with Mantel tests. KEY RESULTS: The six populations of Silene latifolia investigated showed significant molecular and quantitative genetic differentiation. Geographic and phenotypic distances were significantly associated. Age at first flowering increased significantly with latitude and exhibited a Q(st) value of 0.17 in females and 0.10 in males, consistent with adaptation to local environmental conditions. By contrast, no evidence of isolation-by-distance and no significant association between molecular and phenotypic distances were found. CONCLUSIONS: Significant molecular genetic divergence among populations of Silene latifolia, from the European native range is consistent with known limited seed and pollen flow distances, while significant quantitative genetic divergence among populations and clinal variation for age at first flowering suggest local adaptation