Trade-off between morphological convergence and opportunistic diet behavior in fish hybrid zone

<p>Abstract</p> <p>Background</p> <p>The invasive <it>Chondrostoma nasus nasus </it>has colonized part of the distribution area of the protected endemic species <it>Chondrostoma toxostoma toxostoma</it>. This hybrid zone is a complex system where multiple effects such as inter-species competition, bi-directional introgression, strong environmental pressure and so on are combined. Why do sympatric <it>Chondrostoma </it>fish present a unidirectional change in body shape? Is this the result of inter-species interactions and/or a response to environmental effects or the result of trade-offs? Studies focusing on the understanding of a trade-off between multiple parameters are still rare. Although this has previously been done for Cichlid species flock and for Darwin finches, where mouth or beak morphology were coupled to diet and genetic identification, no similar studies have been done for a fish hybrid zone in a river. We tested the correlation between morphology (body and mouth morphology), diet (stable carbon and nitrogen isotopes) and genomic combinations in different allopatric and sympatric populations for a global data set of 1330 specimens. To separate the species interaction effect from the environmental effect in sympatry, we distinguished two data sets: the first one was obtained from a highly regulated part of the river and the second was obtained from specimens coming from the less regulated part.</p> <p>Results</p> <p>The distribution of the hybrid combinations was different in the two part of the sympatric zone, whereas all the specimens presented similar overall changes in body shape and in mouth morphology. Sympatric specimens were also characterized by a larger diet behavior variance than reference populations, characteristic of an opportunistic diet. No correlation was established between the body shape (or mouth deformation) and the stable isotope signature.</p> <p>Conclusion</p> <p>The Durance River is an untamed Mediterranean river despite the presence of numerous dams that split the river from upstream to downstream. The sympatric effect on morphology and the large diet behavior range can be explained by a tendency toward an opportunistic behavior of the sympatric specimens. Indeed, the similar response of the two species and their hybrids implied an adaptation that could be defined as an alternative trade-off that underline the importance of epigenetics mechanisms for potential success in a novel environment.</p

L’histoire évolutive de Neandertal et Denisova vue par les systèmes des groupes sanguins

Malgré une cartographie toujours plus fine des génomes de Néandertal et de Denisova, on sait peu de choses sur les groupes sanguins des globules rouges de ces populations archaïques. Notre objectif est d’identifier le polymorphisme des groupes sanguins néandertaliens et denisoviens afin de retracer la diversité humaine archaïque et actuelle, puis de discuter des aspects sanitaires et des vulnérabilités des populations archaïques. Nous avons analysé les séquences de haute qualité de trois Néan..

Structure génétique de la population de la région PACA du XIXe siècle à partir des patronymes

L’analyse de la distribution des patronymes à travers le temps et l’espace permet d’appréhender la structure des populations. L’étude de la diversité des stocks patronymiques rend possible l’observation des échanges entre les populations ou leur possible isolation. Dans la littérature scientifique, il a été montré que la région PACA était relativement isolée et différente sur la base des patronymes du reste de la France du XXe et du XXIe siècle. Classiquement les études analysant la structure..

Development of 55 novel polymorphic microsatellite loci for the critically endangered L. (Actinopterygii: Perciformes: Percidae) and cross-species amplification in five other percids

International audienceBy combining biotin-enrichment protocol and next generation pyrosequencing, through 454 GS-FLX Titanium technology, 55 polymorphic microsatellites loci with perfect motif were isolated from the Rhone streber (), a critically endangered European fish species. Eight multiplex PCR kits were optimised in order to genotype a total of 58 polymorphic loci, including three previously published loci. The level of genetic diversity was assessed for 68 , 30 , 33 and four individuals. Amplification success was also assessed on and using single individuals. These markers will be useful to investigate the population structure of the highly fragmented Rhone streber. They represent a powerful tool for conservation issues and evolutionary approaches of this endemic species. Moreover, part of our markers demonstrated applicability to other percid species, allowing for potential applications to fisheries and aquaculture management

Cross-species amplification of 41 microsatellites in European cyprinids: A tool for evolutionary, population genetics and hybridization studies

<p>Abstract</p> <p>Background</p> <p>Cyprinids display the most abundant and widespread species among the European freshwater Teleostei and are known to hybridize quite commonly. Nevertheless, a limited number of markers for conducting comparative differentiation, evolutionary and hybridization dynamics studies are available to date.</p> <p>Findings</p> <p>Five multiplex PCR sets were optimized in order to assay 41 cyprinid-specific polymorphic microsatellite loci (including 10 novel loci isolated from <it>Chondrostoma nasus nasus, Chondrostoma toxostoma toxostoma </it>and <it>Leuciscus leuciscus</it>) for 503 individuals (440 purebred specimens and 63 hybrids) from 15 European cyprinid species. The level of genetic diversity was assessed in <it>Alburnus alburnus, Alburnoides bipunctatus, C. genei, C. n. nasus, C. soetta, C. t. toxostoma, L. idus, L. leuciscus, Pachychilon pictum, Rutilus rutilus, Squalius cephalus </it>and <it>Telestes souffia</it>. The applicability of the markers was also tested on <it>Abramis brama, Blicca bjoerkna </it>and <it>Scardinius erythrophtalmus </it>specimens. Overall, between 24 and 37 of these markers revealed polymorphic for the investigated species and 23 markers amplified for all the 15 European cyprinid species.</p> <p>Conclusions</p> <p>The developed set of markers demonstrated its performance in discriminating European cyprinid species. Furthermore, it allowed detecting and characterizing hybrid individuals. These microsatellites will therefore be useful to perform comparative evolutionary and population genetics studies dealing with European cyprinids, what is of particular interest in conservation issues and constitutes a tool of choice to conduct hybridization studies.</p

Genes flow by the channels of culture: the genetic imprint of matrilocality in Ngazidja, Comoros Islands

International audienc

Treat-to-target in systemic lupus erythematosus: recommendations from an international task force.

The principle of treating-to-target has been successfully applied to many diseases outside rheumatology and more recently to rheumatoid arthritis. Identifying appropriate therapeutic targets and pursuing these systematically has led to improved care for patients with these diseases and useful guidance for healthcare providers and administrators. Thus, an initiative to evaluate possible therapeutic targets and develop treat-to-target guidance was believed to be highly appropriate in the management of systemic lupus erythematosus (SLE) patients as well. Specialists in rheumatology, nephrology, dermatology, internal medicine and clinical immunology, and a patient representative, contributed to this initiative. The majority convened on three occasions in 2012-2013. Twelve topics of critical importance were identified and a systematic literature review was performed. The results were condensed and reformulated as recommendations, discussed, modified and voted upon. The finalised bullet points were analysed for degree of agreement among the task force. The Oxford Centre level of evidence (LoE, corresponding to the research questions) and grade of recommendation (GoR) were determined for each recommendation. The 12 systematic literature searches and their summaries led to 11 recommendations. Prominent features of these recommendations are targeting remission, preventing damage and improving quality of life. LoE and GoR of the recommendations were variable but agreement was >0.9 in each case. An extensive research agenda was identified, and four overarching principles were also agreed upon. Treat-to-target-in-SLE (T2T/SLE) recommendations were developed by a large task force of multispecialty experts and a patient representative. It is anticipated that 'treating-to-target' can and will be applicable to the care of patients with SLE

A framework for remission in SLE: consensus findings from a large international task force on definitions of remission in SLE (DORIS)

Objectives Treat-to-target recommendations have identified 'remission' as a target in systemic lupus erythematosus (SLE), but recognise that there is no universally accepted definition for this. Therefore, we initiated a process to achieve consensus on potential definitions for remission in SLE. Methods An international task force of 60 specialists and patient representatives participated in preparatory exercises, a face-to-face meeting and follow-up electronic voting. The level for agreement was set at 90%. Results The task force agreed on eight key statements regarding remission in SLE and three principles to guide the further development of remission definitions: 1. Definitions of remission will be worded as follows: remission in SLE is a durable state characterised by . (reference to symptoms, signs, routine labs). 2. For defining remission, a validated index must be used, for example, clinical systemic lupus erythematosus disease activity index (SLEDAI)=0, British Isles lupus assessment group (BILAG) 2004 D/E only, clinical European consensus lupus outcome measure (ECLAM)=0; with routine laboratory assessments included, and supplemented with physician's global assessment. 3. Distinction is made between remission off and on therapy: remission off therapy requires the patient to be on no other treatment for SLE than maintenance antimalarials; and remission on therapy allows patients to be on stable maintenance antimalarials, low-dose corticosteroids (prednisone ≤5 mg/day), maintenance immunosuppressives and/or maintenance biologics. The task force also agreed that the most appropriate outcomes (dependent variables) for testing the prognostic value (construct validity) of potential remission definitions are: death, damage, flares and measures of health-related quality of life. Conclusions The work of this international task force provides a framework for testing different definitions of remission against long-term outcomes

From Late Miocene to Holocene: Processes of Differentiation within the Telestes Genus (Actinopterygii: Cyprinidae)

Investigating processes and timing of differentiation of organisms is critical in the understanding of the evolutionary mechanisms involved in microevolution, speciation, and macroevolution that generated the extant biodiversity. From this perspective, the Telestes genus is of special interest: the Telestes species have a wide distribution range across Europe (from the Danubian district to Mediterranean districts) and have not been prone to translocation. Molecular data (mtDNA: 1,232 bp including the entire Cyt b gene; nuclear genome: 11 microsatellites) were gathered from 34 populations of the Telestes genus, almost encompassing the entire geographic range. Using several phylogenetic and molecular dating methods interpreted in conjunction with paleoclimatic and geomorphologic evidence, we investigated the processes and timing of differentiation of the Telestes lineages. The observed genetic structure and diversity were largely congruent between mtDNA and microsatellites. The Messinian Salinity Crisis (Late Miocene) seems to have played a major role in the speciation processes of the genus. Focusing on T. souffia, a species occurring in the Danube and Rhone drainages, we were able to point out several specific events from the Pleistocene to the Holocene that have likely driven the differentiation and the historical demography of this taxon. This study provides support for an evolutionary history of dispersal and vicariance with unprecedented resolution for any freshwater fish in this region

Representativeness of microsatellite distributions in genomes, as revealed by 454 GS-FLX Titanium pyrosequencing

<p>Abstract</p> <p>Background</p> <p>Microsatellites are markers of choice in population genetics and genomics, as they provide useful insight into patterns and processes as diverse as genome evolutionary dynamics and demographic processes. The acquisition of microsatellites through multiplex-enriched libraries and 454 GS-FLX Titanium pyrosequencing is a promising new tool for the isolation of new markers in unknown genomes. This approach can also be used to evaluate the extent to which microsatellite-enriched libraries are representative of the genome from which they were isolated. In this study, we deciphered potential discrepancies in microsatellite content recovery for two reference genomes (<it>Apis mellifera </it>and <it>Danio rerio</it>), selected on the basis of their extreme heterogeneity in terms of the proportions and distributions of microsatellites on chromosomes.</p> <p>Results</p> <p>The <it>A. mellifera </it>genome, in particular, was found to be highly heterogeneous, due to extremely high rates of recombination, with hotspots, but the only bias consistently introduced into pyrosequenced multiplex-enriched libraries concerned sequence length, with the overrepresentation of sequences 160 to 320 bp in length. Other deviations from expected proportions or distributions of motifs on chromosomes were observed, but the significance and intensity of these deviations was mostly limited. Furthermore, no consistent adverse competition between multiplexed probes was observed during the motif enrichment phase.</p> <p>Conclusions</p> <p>This approach therefore appears to be a promising strategy for improving the development of microsatellites, as it introduces no major bias in terms of the proportions and distribution of microsatellites.</p