Permanent Genetic Resources added to Molecular Ecology Resources Database 1 April 2011-31 May 2011

This article documents the addition of 92 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Anopheles minimus, An. sinensis, An. dirus, Calephelis mutica, Lutjanus kasmira, Murella muralis and Orchestia montagui. These loci were cross-tested on the following species: Calephelis arizonensi, Calephelis borealis, Calephelis nemesis, Calephelis virginiensis and Lutjanus bengalensis

Structures génétique et démographique des populations de deux espèces d'ophiures aux caractéristiques biologiques contrastées, Acrocnida brachiata et Ophiothrix fragilis, en Atlantique Nord-Est

Nowadays species distribution mainly depends on population history and abilities of migrants to colonize new territories. Dispersal capacities of marine organisms are mainly related to the time spent in the water column by larvae and by habitat fragmentation. Two species of brittle-star of the North-East Atlantic, A. brachiata and O.fragilis, which show different life history traits, have been studied. Parallel population genetics and dynamics approaches have been chosen in the aim of better delineate how past and present gene flow may explain the actual distribution of species. A. brachiata includes two ecotypic sibling species which diverge 5 My ago, at the Mio-Pliocene transition. One lineage lives in intertidal, the second in subtidal. Colonization history seems to differ between these two lineages, because of different glacial refugia localisation. Populations are highly genetically structured: flow is mainly reduced due to a short larval phase and the high level of habitat fragmentation. Hybridization between lineages occur at low rate due to selection against hybrids in both habitat during recruitment. Adult migration might occur and is likely to homogenise genetic structure at microspatial scale. Demographic functioning seems to show a pluri-annual cycle as annual recruitment seems insufficient to ensure population sustainability. O. fragilis is also a complex of two sibling species, one in the Southern Europe, the other one on North- Atlantic coasts. The latter is divided into two ecotypic varieties, one mainly adapted to subtidal life, the other to the intertidal one. Co-occurrence of the two varieties induces a first level of genetic structure. Actually, most of the genetic structure is due to local processes and not to geographical isolation, in agreement with a species displaying a long larval phase and living in continuous habitat. These local processes seem to induce a temporal Walhund effect, probably due to a metapopulation functioning. Great disparities in population dynamics between sites may also contribute to the chaotic genetic structure of populations. Results obtained for these two species provide new insights on how past history influence species distribution and how local processes play a major role in structuring populations.La distribution des espèces dépend de leur histoire évolutive et de leur capacité à disperser et coloniser de nouveaux territoires. En milieu marin, cette capacité de dispersion est conditionnée par la durée de la phase larvaire et la répartition plus ou moins continue de leur habitat. Afin de mieux comprendre la part respective de ces différents facteurs, l’histoire passée et contemporaine des populations a été étudiée, par le biais de la génétique et de la dynamique des populations, pour deux espèces d’ophiures de l’Atlantique Nord-Est, A. brachiata et O.fragilis, qui présentent des caractéristiques biologiques contrastées. L’espèce A. brachiata est constituée de deux lignées écotypiques dont la spéciation aurait été de nature allopatrique à la transition Mio-Pliocène (5 MA). Chaque lignée se répartit préférentiellement à un étage bathymétrique, l’une en milieu subtidal et l’autre en milieu intertidal, avec une histoire de colonisation de l’habitat propre à chaque lignée, depuis des refuges glaciaires différents. Les échanges entre populations sont très faibles, en raison de la fragmentation de l’habitat sablo-vaseux et de la phase dispersive courte (quatre jours). Des phénomènes d’hybridation rares sont observés entre lignées et apparaissent fortement contre-sélectionnés par l’habitat lors de la phase de recrutement. Des mécanismes de migration d’adultes semblent homogénéiser les populations à micro-échelle. Le fonctionnement des populations d’A. brachiata ne semble pas suivre un rythme de renouvellement annuel mais plutôt se faire par des épisodes de recrutement plus conséquents certaines années. L’espèce O. fragilis est également constituée de deux lignées génétiques dont l’une est inféodée à la Méditerranée et aux côtes de la péninsule ibérique tandis que l’autre est présente sur les côtes bretonnes et de la Manche. Cette seconde lignée se subdivise en deux variétés écotypiques, l’une vraisemblablement adaptée à une vie subtidale grégaire et l’autre à des habitats intertidaux. L’existence de ces variétés induit un premier niveau de structure génétique relativement faible. En dépit du fait que l’espèce vit majoritairement sur des fonds caillouteux qui forment un continuum d’habitats favorables en Manche et que la durée de sa phase larvaire soit longue (environ 21 jours), la structure des populations d’O. fragilis semble être le reflet de processus locaux, tels que des effets Walhund temporels, plutôt que celui des processus d’isolement géographique. Le fonctionnement démographique d’O. fragilis montre d’importantes disparités entre sites, qui peuvent également contribuer à la structure globale de l’espèce. L’ensemble de ces résultats, mis en parallèle, souligne l’importance des processus historiques dans la répartition globale de l’espèce et celle des processus locaux dans la structure contemporaine des populations

Structures génétique et démographique des populations de deux espèces d'ophiures aux caractéristiques biologiques contrastées, Acrocnida brachiata et Ophiothrix fragilis, an Atlantique Nord-Est

La génétique et la dynamique des populations sont étudiées pour deux espèces d ophiures de l Atlantique Nord-Est. L espèce A. brachiata est constituée de deux lignées écotypiques, avec une histoire de colonisation propre à chaque lignée. Les échanges entre populations sont très faibles (fragmentation de l habitat et phase dispersive courte). Le fonctionnement démographique d A. brachiata suit un rythme de renouvellement pluri-annuel. La structure génétique d O. fragilis semble peu dépendante de l existence des deux variétés écotypiques mais plus le reflet de processus locaux (e.g. effets Walhund temporels). Le fonctionnement démographique montre d importantes disparités entre sites, qui peuvent contribuer à la structure globale de l espèce. L ensemble de ces résultats, mis en parallèle, souligne l importance des processus historiques dans la répartition globale de l espèce et celle des processus locaux dans la structure contemporaine des populations.PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocROSCOFF-Observ.Océanol. (292393008) / SudocSudocFranceF

Genetic structure of the reef grouper Epinephelus merra in the West Indian Ocean appears congruent with biogeographic and oceanographic boundaries

The reef fauna connectivity of the West Indian Ocean (WIO) is one of the least studied globally. Here we use genetic analyses of the grouper Epinephelus merra (Bloch 1793) to determine patterns of connectivity and to identify barriers to dispersal in this WIO marine area. Phylogeographic and population-level analyses were conducted on cytochrome b sequences and microsatellites (13 loci) from 557 individuals sampled in 15 localities distributed across the West Indian Ocean. Additional samples from the Pacific Ocean were used to benchmark the WIO population structure. The high level of divergence revealed between Indian and Pacific localities (of about 4.5% in sequences) might be the signature of the major tectonic and climatic changes operating at the Plio-Pleistocene transition, congruently with numerous examples of Indo-Pacific speciation. In comparison, the E. merra sequences from the Indian Ocean constitute a monophyletic clade with a low average genetic distance (d < 0.5%). However both genetic markers indicated some structure within this ocean. The main structure revealed was the isolation of the Maldives from the WIO localities (a different group signature identified by clustering analysis, great values of differentiation). Both marker types reveal further significant structure within the WIO, mainly the isolation of the Mascarene Islands (significant AMOVA and isolation-by-distance patterns) and some patchy structure between the northernmost localities and within the Mozambique Channel. The WIO genetic structure of E. merra appeared congruent with main biogeographic boundaries and oceanographic currents

Local scale connectivity in the cave-dwelling brooding fish Apogon imberbis

International audienceA lower degree of population connectivity is generally expected for species living in a naturally fragmented habitat than for species living in a continuum of suitable environment. Due to clear-cut environmental conditions with the surrounding littoral zone, underwater marine caves of the Mediterranean Sea constitute a good model to explore the effect of habitat discontinuity on the population structure of their inhabitants. With this goal, the genetic population structure of Apogon imberbis, a mouth-brooding teleost, was explored using the mitochondrial cytochrome b gene and 7 nuclear microsatellite loci from 164 fishes sampled at the micro-scale (ca. 40 km) of the Marseille area (Bay of Marseille and Calanques coast, in NW Mediterranean). Both marker types indicated a low level of genetic structure within the studied area. We propose that each suitable crack and cavity is used as a stepping-stone habitat between disconnected large cave-habitats. This, together with larval dispersal, ensures enough gene flow between caves to homogenize the genetic pattern at microscale while isolation by distance and by open waters could explain the small structure observed. The present study indicates that the effect of natural fragmentation in connectivity disruption can largely be counter-balanced by life history traits and overlooked details in habitat preferences. (C) 2014 Elsevier B.V. All rights reserved

Gender of hallucination-like speech affects auditory cortical response differently in both male and female listeners: A functional magnetic resonance imaging (FMRI) study

<div><p>Genetic population structure of swordfish <i>Xiphias gladius</i> was examined based on 2231 individual samples, collected mainly between 2009 and 2010, among three major sampling areas within the Indian Ocean (IO; twelve distinct sites), Atlantic (two sites) and Pacific (one site) Oceans using analysis of nineteen microsatellite loci (n = 2146) and mitochondrial ND2 sequences (n = 2001) data. Sample collection was stratified in time and space in order to investigate the stability of the genetic structure observed with a special focus on the South West Indian Ocean. Significant AMOVA variance was observed for both markers indicating genetic population subdivision was present between oceans. Overall value of F-statistics for ND2 sequences confirmed that Atlantic and Indian Oceans swordfish represent two distinct genetic stocks. Indo-Pacific differentiation was also significant but lower than that observed between Atlantic and Indian Oceans. However, microsatellite F-statistics failed to reveal structure even at the inter-oceanic scale, indicating that resolving power of our microsatellite loci was insufficient for detecting population subdivision. At the scale of the Indian Ocean, results obtained from both markers are consistent with swordfish belonging to a single unique panmictic population. Analyses partitioned by sampling area, season, or sex also failed to identify any clear structure within this ocean. Such large spatial and temporal homogeneity of genetic structure, observed for such a large highly mobile pelagic species, suggests as satisfactory to consider swordfish as a single panmictic population in the Indian Ocean.</p></div

Restricted dispersal of the reef fish Myripristis berndti at the scale of the SW Indian Ocean

The reef fish Myripristis berndti (Jordan & Everman 1903) is a pantropical species. A genetic analysis was conducted on 353 individuals from 10 localities distributed across the SW Indian Ocean (SWIO) in order to determine patterns of connectivity in the SWIO. Both the mtDNA sequences (711-bp cytochrome b sequences) and the microsatellites (8 newly developed loci) reveal spatial patterns of differentiation within the SWIO. There is, however, a discrepancy between the structure observed with each kind of marker. MtDNA revealed that 3 peripheral populations (NW Kenya, SE Reunion, and SW Europa) were isolated from the 7 more central populations, which form a more densely connected population network, while microsatellite data indicated a more restricted connectivity with significant differentiation between most pairs of localities. Higher genetic differences between Reunion and Europa were found, which might be explained by geography and isolation by distance pattern. In contrast, the genetic signature of Kenya-the most divergent locality identified by mtDNA basis but not with microsatellite-was probably the consequence of a particular colonisation history. These results indicate a much more restricted connectivity than previously thought for this species

Population structure enhances perspectives on regional management of the western Indian Ocean green turtle

To refine our understanding of the spatial structure of the green turtle (Chelonia mydas) populations in the South West Indian Ocean (SWIO), we analysed patterns of mitochondrial DNA (396 base pairs control region fragment) variation among 171 samples collected at five distinct locations (Kenya, Northern Mozambique, and three locations in the Republic of Seychelles: the Granitic, Amirantes, and Farquhar groups) and compared them to genetic data (n = 288), previously collected from 10 southern locations in the SWIO. We also analysed post-nesting satellite tracks (n = 4) from green turtles nesting in the Amirantes group. Pairwise comparisons of haplotype frequencies showed significant genetic differentiation amongst rookeries and suggest that the SWIO hosts two main genetic stocks of nesting green turtles that could themselves be divided in two sub-stocks that still need to be confirmed: A. the Southern Mozambique Channel, that could be composed of two sub-stocks (a1) Europa and (a2) Juan de Nova, and B. the Northern SWIO (N-SWIO) comprising two sub-stocks (b1) the Seychelles archipelago stock—SEY; and (b2) the remaining Northern SWIO rookeries. The newly revealed differentiation of the Seychelles population is supported by restricted migration of females tracked from the Amirantes group suggesting relatively limited links with other regional stocks. We hypothesize that this differentiation could be due to local and regional current patterns and to the role of the Indo-Pacific Barrier as a genetic break, enhanced during periods of sea level decrease associated with a rare but continuous flow of hatchlings and young juveniles from Western Australia