Molecular evidence for the coexistence of two sibling species in Pylaiella littoralis (Ectocarpales, Phaeophyceae) along the Brittany coast

International audienceThe great phenotypic variability and the lack of diagnostic characters in the genus Pylaiella render the systematic study of this genus problematic. In this study, we investigated the diversity of Pylaiella littoralis along the Brittany (France) coast using a DNA barcoding multilocus approach with mitochondrial (cox1, nad1, and atp9) and chloroplastic (rbcL and atpB) markers associated with a population genetics approach using 10 microsatellite markers. In addition, spatio-temporal sampling was conducted along the Brittany coast. We sampled 140 individuals from four sites located between Saint-Malo and Concarneau (380 km) from April to October. Mitochondrial sequence data revealed the occurrence of two sibling species, with a minimum of 2.4% divergence between them. Microsatellite genotypic data congruently revealed two well-supported clusters matching the two mitochondrial clades of Pylaiella. Although gene flow is limited between species, occurrence of genetic admixtures in some populations suggested that reproductive isolation is not complete. Our study highlighted the complementarity of barcoding and population genetics approaches to shed light on the evolutionary processes that lead to speciation

Understanding ecological functionning of ecological habitats, and building New Indicators based on Genetic Tools to assess their GES (Good Environmental Status).

International audienceThe coralligenous is a typical Mediterranean marine habitat and hosts the highest concentration of biodiversity of this sea. Paradoxically, unlike Posidonia meadows, it is poorly studied. Like the famous tropical coral reefs, it is a complex biogenic habitat, based on encrusting red algae (numerous metazoan phyla also participate to bio-construction)(Ballesteros 2006). Concerning societal interest coralligenous habitats are known to be very attractive diving spots and but the importance of this ecosystems for fisheries The societal interest relies on the setup of innovative, cost-effective and accurate methods for biodiversity characterization and monitoring, based on genetic tools rigorously inter-calibrated with traditional taxonomy and photo-quadrate approaches. The aim of this project is to improve our understanding of its functioning and resilience capacity, and establish biodiversity and connectivity patterns among localities and ecological profiles, providing information for rationalizing the design of Marine Protected Area networks and monitoring methods. To reach this goal, synergy of interdisciplinarity will be used, combining population genetics, community ecology, microbial ecology and physical oceanography. This requests four tasks, partly using the same data, but different analysis methods. 1- Establishment of the taxonomic composition of the engineer corallinale algae. Several cryptic species in red algae were revealed by genetic markers (cf. B-4). Molecular tools (IMBE) and classical taxonomy (Dr Marc Verlaque, MIO) will be used 2- Establishment of the species composition for numerous small quadrates of coralligenous using meta-barcoding in different ecological profiles 3- Population structure and phylogeography of two selected taxa: a red alga Lithophyllum spp. and a bryozoan Myriapora truncata, on the CIGESMED sampling network, contextualized by ecological factors (cf above). 4- Synthesis and Comparisons: Propose new GES (good environmental status) indicators for the coralligenous and biodiversity management rules

Understanding ecological functionning of ecological habitats, and building New Indicators based on Genetic Tools to assess their GES (Good Environmental Status).

International audienceThe coralligenous is a typical Mediterranean marine habitat and hosts the highest concentration of biodiversity of this sea. Paradoxically, unlike Posidonia meadows, it is poorly studied. Like the famous tropical coral reefs, it is a complex biogenic habitat, based on encrusting red algae (numerous metazoan phyla also participate to bio-construction)(Ballesteros 2006). Concerning societal interest coralligenous habitats are known to be very attractive diving spots and but the importance of this ecosystems for fisheries The societal interest relies on the setup of innovative, cost-effective and accurate methods for biodiversity characterization and monitoring, based on genetic tools rigorously inter-calibrated with traditional taxonomy and photo-quadrate approaches. The aim of this project is to improve our understanding of its functioning and resilience capacity, and establish biodiversity and connectivity patterns among localities and ecological profiles, providing information for rationalizing the design of Marine Protected Area networks and monitoring methods. To reach this goal, synergy of interdisciplinarity will be used, combining population genetics, community ecology, microbial ecology and physical oceanography. This requests four tasks, partly using the same data, but different analysis methods. 1- Establishment of the taxonomic composition of the engineer corallinale algae. Several cryptic species in red algae were revealed by genetic markers (cf. B-4). Molecular tools (IMBE) and classical taxonomy (Dr Marc Verlaque, MIO) will be used 2- Establishment of the species composition for numerous small quadrates of coralligenous using meta-barcoding in different ecological profiles 3- Population structure and phylogeography of two selected taxa: a red alga Lithophyllum spp. and a bryozoan Myriapora truncata, on the CIGESMED sampling network, contextualized by ecological factors (cf above). 4- Synthesis and Comparisons: Propose new GES (good environmental status) indicators for the coralligenous and biodiversity management rules

Small-scale connectivity of coralligenous habitats: insights from a modelling approach within a semi-opened Mediterranean bay

International audienc

Biodiversity, climate change, and adaptation in the Mediterranean

Potential for, and limits to, adaptation to environmental changes are critical for resilience and risk mitigation. The Mediterranean basin is a mosaic of biodiversity-rich ecosystems long affected by human influence, whose resilience is now questioned by climate change. After reviewing the different components of biological adaptation, we present the main characteristics of marine and terrestrial biodiversity in the Mediterranean basin and of the pressures they face. Taking climatic trends into consideration, we discuss the adaptive potential of a range of ecosystems dominated by species without active dispersal. We argue that the high heterogeneity of Mediterranean landscapes and seascapes constitutes a laboratory for the study of adaptation when environmental conditions change rapidly and may provide opportunities for adaptation and adaptability of species and ecosystems. Adaptive management in the Mediterranean can and should harness the nature-based solutions offered by both ecological and evolutionary processes for increasing the resilience of ecosystems to climate change

Type 3 long QT syndrome: Is the effectiveness of treatment with beta-blockers population-specific?

International audienceBackground: The efficacy of beta-blocker treatment in type 3 long QT syndrome (LQT3) remains debated.Objectives: The purpose of this study was to test the hypothesis that beta-blocker use is associated with cardiac events (CEs) in a French cohort of LQT3 patients.Methods: All patients with a likely pathogenic/pathogenic variant in the SCN5A gene (linked to LQT3) were included and followed-up. Documented ventricular tachycardia/ventricular fibrillation, torsades de pointes, aborted cardiac arrest, sudden death, and appropriate shocks were considered as severe cardiac events (SCEs). CEs also included syncope.Results: We included 147 patients from 54 families carrying 23 variants. Six of the patients developed symptoms before the age of 1 year and were analyzed separately. The 141 remaining patients (52.5% male; median age at diagnosis 24.0 years) were followed-up for a median of 11 years. The probabilities of a CE and an SCE from birth to the age of 40 were 20.5% and 9.9%, respectively. QTc prolongation (hazard ratio [HR] 1.12 [1.0-1.2]; P = .005]) and proband status (HR 4.07 [1.9-8.9]; P <.001) were independently associated with the occurrence of CEs. Proband status (HR 8.13 [1.7-38.8]; P = .009) was found to be independently associated with SCEs, whereas QTc prolongation (HR 1.11 [1.0-1.3]; P = .108) did not reach statistical significance. The cumulative probability of the age at first CE/SCE was not lower in patients treated with a beta-blocker.Conclusion: In agreement with the literature, proband status and lengthened QTc were associated with a higher risk of CEs. Our data do not show a protective effect of beta-blocker treatment