Speciation in the Deep Sea: Multi-Locus Analysis of Divergence and Gene Flow between Two Hybridizing Species of Hydrothermal Vent Mussels

International audienceBackground: Reconstructing the history of divergence and gene flow between closely-related organisms has long been a difficult task of evolutionary genetics. Recently, new approaches based on the coalescence theory have been developed to test the existence of gene flow during the process of divergence. The deep sea is a motivating place to apply these new approaches. Differentiation by adaptation can be driven by the heterogeneity of the hydrothermal environment while populations should not have been strongly perturbed by climatic oscillations, the main cause of geographic isolation at the surface. Methodology/Principal Finding: Samples of DNA sequences were obtained for seven nuclear loci and a mitochondrial locus in order to conduct a multi-locus analysis of divergence and gene flow between two closely related and hybridizing species of hydrothermal vent mussels, Bathymodiolus azoricus and B. puteoserpentis. The analysis revealed that (i) the two species have started to diverge approximately 0.760 million years ago, (ii) the B. azoricus population size was 2 to 5 time greater than the B. puteoserpentis and the ancestral population and (iii) gene flow between the two species occurred over the complete species range and was mainly asymmetric, at least for the chromosomal regions studied. Conclusions/Significance: A long history of gene flow has been detected between the two Bathymodiolus species. However, it proved very difficult to conclusively distinguish secondary introgression from ongoing parapatric differentiation. As powerful as coalescence approaches could be, we are left by the fact that natural populations often deviates from standard assumptions of the underlying model. A more direct observation of the history of recombination at one of the seven loci studied suggests an initial period of allopatric differentiation during which recombination was blocked between lineages. Even in the deep sea, geographic isolation may well be a crucial promoter of speciation

Searching for answers and validation Australian women's experiences of coping with the adverse sexual effects of antidepressants /

Sexual difficulties relating to selective serotonin reuptake inhibitor (SSRI) medication have an impact on quality of life and are a common cause for non-adherence to medication. While most research has focussed on the prevalence and treatment of sexual difficulties, little is known about how patients cope with the adverse sexual effects of SSRIs. This qualitative study, using Interpretive Phenomenological Analysis (IPA), investigated the experiences of 10 Australian women currently coping with the adverse sexual effects of this antidepressant by conducting semi-structured interviews. This paper presents one major theme from the study and reports the findings related to women’s self-reported experiences of interacting with GPs in their search for answers and validation of their concerns. Findings from the study add to the current literatureby providing an insight into how interactions with GPs impact on women’s abilities to cope with adverse sexual effects. Empathic discussions and shared decision-making between GPs and women can provide the opportunity to improve the management of the adverse sexual effects of SSRIs and may lead to improved outcomes for women

'Accepting what is': an approach for managing the long-term sexual side effects of selective serotonin reuptake inhibitors (SSRIs) in women

Sexual difficulties may not be a pressing issue for women on antidepressants during the early phase of selective serotonin reuptake inhibitor (SSRI) treatment; however, this can emerge as a substantial problem once women are stabilised on medication. Little is known about how women cope with the adverse sexual effects of SSRIs. This qualitative study used Interpretative Phenomenological Analysis to explore the experiences of Australian women currently coping with the sexual side effects of this antidepressant. Interviews were conducted with 10 heterosexual women, aged 45 years and younger. Four major coping strategies were identified “searching”, “suffering in silence”, “trying to resolve” and “accepting what is”. This paper explores one particular response “accepting what is”, which includes a number of strategies commonly employed by women on long-term medication. Findings from the study have particular relevance for sex and relationship therapists and may assist women in managing sexual side effects that are perceived to be beyond their control. This paper adds to the current literature by increasing understanding of how “accepting what is” can be a step forward, particularly for women who have chosen to remain on long-term medication. In theoretical terms, a deeper understanding of how women cope could inform debate about the appropriate management of long-term sexual side effects in the absence of effective pharmacological interventions

Moytirra: Discovery of the first known deep-sea hydrothermal vent field on the slow-spreading Mid-Atlantic Ridge north of the Azores

Geological, biological, morphological, and hydrochemical data are presented for the newly discovered Moytirra vent field at 45oN. This is the only high temperature hydrothermal vent known between the Azores and Iceland, in the North Atlantic and is located on a slow to ultraslow-spreading mid-ocean ridge uniquely situated on the 300 m high fault scarp of the eastern axial wall, 3.5 km from the axial volcanic ridge crest. Furthermore, the Moytirra vent field is, unusually for tectonically controlled hydrothermal vents systems, basalt hosted and perched midway up on the median valley wall and presumably heated by an off-axis magma chamber. The Moytirra vent field consists of an alignment of four sites of venting, three actively emitting “black smoke,” producing a complex of chimneys and beehive diffusers. The largest chimney is 18 m tall and vigorously venting. The vent fauna described here are the only ones documented for the North Atlantic (Azores to Reykjanes Ridge) and significantly expands our knowledge of North Atlantic biodiversity. The surfaces of the vent chimneys are occupied by aggregations of gastropods (Peltospira sp.) and populations of alvinocaridid shrimp (Mirocaris sp. with Rimicaris sp. also present). Other fauna present include bythograeid crabs (Segonzacia sp.) and zoarcid fish (Pachycara sp.), but bathymodiolin mussels and actinostolid anemones were not observed in the vent field. The discovery of the Moytirra vent field therefore expands the known latitudinal distributions of several vent-endemic genera in the north Atlantic, and reveals faunal affinities with vents south of the Azores rather than north of Iceland