177 research outputs found
Body-Focused Repetitive Behaviors and Non-Suicidal Self-Injury: A Comparison of Clinical Characteristics and Symptom Features
Body-focused repetitive behaviors (BFRBs) and non-suicidal self-injury (NSSI) are recognized as distinct categories in the DSM-5. However, definitions and assessment of NSSI sometimes encompasses behaviors similar to BFRBs, and little data exist about their clinical differences. The current study examined clinical characteristics and symptom features associated with NSSI vs. BFRBs. The current sample included 1523 individuals who endorsed moderate to severe NSSI (n = 165) or BFRBs: hair pulling group (n = 102), skin picking group (n = 216), nail picking group (n = 253), nail biting group (n = 487), and cheek biting group (n = 300). Responders were asked to complete questionnaires on clinical features relevant for BFRBs and NSSI. NSSI and BFRBs had significant differences on several clinical features. Individuals in the NSSI group were more likely than individuals with BFRBs to report engaging in the behavior for social-affective reasons (i.e., to get out of doing something, or receive attention from others). Individuals in the NSSI group were also more likely to engage in the behavior to regulate tension and feelings of emptiness, and to experience relief during the act. In contrast, individuals in the BFRB groups were more likely to engage in the behavior automatically without reflective awareness, to reduce boredom, or to fix appearance. The NSSI group obtained significantly higher scores on questionnaires assessing stress, anxiety, depression, and harm avoidance. Overall, the results showed several notable differences between NSSI and BFRBs that are consistent with clinical literature and definitions of these problems in the DSM-5
Multivariate analysis of morphology, behaviour, growth and developmental timing in hybrids brings new insights into the divergence of sympatric Arctic charr morphs
This work was fully funded by the Icelandic Centre of Research, RANNÍS (Icelandic Research Fund grant no.173802-051).Background: Studying the development of fitness related traits in hybrids from populations diverging in sympatry is a fundamental approach to understand the processes of speciation. However, such traits are often affected by covariance structures that complicate the comprehension of these processes, especially because the interactive relationships between traits of different nature (e.g. morphology, behaviour, life-history) remain largely unknown in this context. In a common garden setup, we conducted an extensive examination of a large suit of traits putatively involved in the divergence of two morphs of Arctic charr (Salvelinus alpinus), and investigated the consequences of potential patterns of trait covariance on the phenotype of their hybrids. These traits were measured along ontogeny and involved growth, yolk sac resorption, developmental timing (hatching and the onset of exogeneous feeding), head morphology and feeding behaviour. Results: Growth trajectories provided the strongest signal of phenotypic divergence between the two charr. Strikingly, the first-generation hybrids did not show intermediate nor delayed growth but were similar to the smallest morph, suggesting parental biases in the inheritance of growth patterns. However, we did not observe extensive multivariate trait differences between the two morphs and their hybrids. Growth was linked to head morphology (suggesting that morphological variations in early juveniles relate to simple allometric effects) but this was the only strong signal of covariance observed between all the measured traits. Furthermore, we did not report evidence for differences in overall phenotypic variance between morphs, nor for enhanced phenotypic variability in their hybrids. Conclusion: Our study shed light on the multivariate aspect of development in a context of adaptive divergence. The lack of evidence for the integration of most traits into a single covariance structure suggested that phenotypic constraints may not always favour nor impede divergence toward ecological niches differing in numerous physical and ecological variables, as observed in the respective habitats of the two charr. Likewise, the role of hybridization as a disruptive agent of trait covariance may not necessarily be significant in the evolution of populations undergoing resource polymorphism.Publisher PDFPeer reviewe
Differentiation at the MHCIIα and Cath2 Loci in Sympatric Salvelinus alpinus Resource Morphs in Lake Thingvallavatn
Publisher's versionNorthern freshwater fish may be suitable for the genetic dissection of ecological traits because they invaded new habitats after the last ice age (∼10.000 years ago). Arctic charr (Salvelinus alpinus) colonizing streams and lakes in Iceland gave rise to multiple populations of small benthic morphotypes, often in sympatry with a pelagic morphotype. Earlier studies have revealed significant, but subtle, genetic differentiation between the three most common morphs in Lake Thingvallavatn. We conducted a population genetic screen on four immunological candidate genes Cathelicidin 2 (Cath2), Hepcidin (Hamp), Liver expressed antimicrobial peptide 2a (Leap-2a), and Major Histocompatibility Complex IIα (MHCIIα) and a mitochondrial marker (D-loop) among the three most common Lake Thingvallavatn charr morphs. Significant differences in allele frequencies were found between morphs at the Cath2 and MHCIIα loci. No such signal was detected in the D-loop nor in the other two immunological genes. In Cath2 the small benthic morph deviated from the other two (FST = 0.13), one of the substitutions detected constituting an amino acid replacement polymorphism in the antimicrobial peptide. A more striking difference was found in the MHCIIα. Two haplotypes were very common in the lake, and their frequency differed greatly between the morphotypes (from 22% to 93.5%, FST = 0.67). We then expanded our study by surveying the variation in Cath2 and MHCIIα in 9 Arctic charr populations from around Iceland. The populations varied greatly in terms of allele frequencies at Cath2, but the variation did not correlate with morphotype. At the MHCIIα locus, the variation was nearly identical to the variation in the two benthic morphs of Lake Thingvallavatn. The results are consistent with a scenario where parts of the immune systems have diverged substantially among Arctic charr populations in Iceland, after colonizing the island ∼10.000 years ago.The Palsson laboratory is supported by Icelandic Research foundation and the University of Iceland research fund. Icelandic research foundation (grant of excellence: nr 100204011) to S.S. Sigurdsson, A. Palsson, B.K. Kristjansson, Zophonias O. Jonsson and Ian A. Johnston paid for part of this work. Kalina H. Kapralova and Johannes Gudbrandsson were supported by the University of Iceland doctoral fund. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer ReviewedRitrýnt tímari
Effects of geothermal effluents on macrobenthic communities in a pristine sub-arctic lake
We studied the effects of warm effluents from the Nesjavellir geothermal power plant on benthic invertebrate communities along a depth gradient of 4 m in lake Þingvallavatn, Iceland. Four study sites were selected: 2 heataffected sites and 2 cold reference sites. Thermal pollution was detected down to 0.4 m at both heat-affected sites, which were 7-12 °C higher than at the same depth at the reference sites. Sustained temperatures ≥27 °C, which is 10-17 °C above ambient water temperatures, seems to be detrimental to the gastropod Radix peregra and several of the littoral chironomid species. Such effects were, however, confined to a small area inside a sheltered rift pool at one of the heat-affected sites. Moderate warming up to ~10 °C above ambient lake temperature in summer, seems to benefit R. peregra, potentially through both a higher survival rate and a shorter life cycle. At the heat-affected sites, sustained high temperatures transformed a relatively diverse chironomid community to a species-poor community, dominated by Paratanytarsus sp. and Cricotopus sylvestris. In contrast, the chironomid Eukiefferiella minor was much more prominent at one of the reference sites. To separate thermal from biological effects, more studies are needed on speciesspecific attributes, including time-series data on growth, survival, and reproduction of the main littoral zoobenthic species. Although our research examined short-term responses of aquatic invertebrates to local thermal stress, our results may also be relevant to long-term responses of freshwater ecosystems at high latitudes to climate change and warming
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Fine-scale parallel patterns in diversity of small benthic Arctic charr (Salvelinus alpinus) in relation to the ecology of lava/groundwater habitats
It is critical to study factors that are important for origin and maintenance of biological
diversity. A comparative approach involving a large number of populations is
particularly useful.We use this approach to study the relationship between ecological
factors and phenotypic diversity in Icelandic Arctic charr (Salvelinus alpinus).
Numerous populations of small benthic charr have evolved in lava springs in Iceland.
These charr appear morphologically similar, but differ in important morphological
features related to feeding. We found a clear relationship between diversity in
morphology, diet, and ecological factors among populations. In particular, there
were clear differences in morphology and diet between fish coming from habitats
where the lava spring flowed on as a stream compared to habitats where the lava
spring flowed into a pond. Our study shows that ecological factors are important
for the origin and maintenance of biological diversity. The relationship between
phenotype and ecological factors are observed on a fine scale, when comparing numerous
populations that are phenotypically similar. This strongly suggests that for
understanding,managing, and conserving biological diversity important ecological
variables have to be taken into the account.Keywords: Adaptation, Morphometrics, Natural selection, Diet, Phenotypic plasticit
Differential gene expression during early development in recently evolved and sympatric Arctic charr morphs
Phenotypic differences between closely related taxa or populations can arise through genetic variation or be environmentally induced, leading to altered transcription of genes during development. Comparative developmental studies of closely related species or variable populations within species can help to elucidate the molecular mechanisms related to evolutionary divergence and speciation. Studies of Arctic charr (Salvelinus alpinus) and related salmonids have revealed considerable phenotypic variation among populations and in Arctic charr many cases of extensive variation within lakes (resource polymorphism) have been recorded. One example is the four Arctic charr morphs in the ∼10,000 year old Lake Thingvallavatn, which differ in numerous morphological and life history traits. We set out to investigate the molecular and developmental roots of this polymorphism by studying gene expression in embryos of three of the morphs reared in a common garden set-up. We performed RNA-sequencing, de-novo transcriptome assembly and compared gene expression among morphs during an important timeframe in early development, i.e., preceding the formation of key trophic structures. Expectedly, developmental time was the predominant explanatory variable. As the data were affected by some form of RNA-degradation even though all samples passed quality control testing, an estimate of 3′-bias was the second most common explanatory variable. Importantly, morph, both as an independent variable and as interaction with developmental time, affected the expression of numerous transcripts. Transcripts with morph effect, separated the three morphs at the expression level, with the two benthic morphs being more similar. However, Gene Ontology analyses did not reveal clear functional enrichment of transcripts between groups. Verification via qPCR confirmed differential expression of several genes between the morphs, including regulatory genes such as AT-Rich Interaction Domain 4A (arid4a) and translin (tsn). The data are consistent with a scenario where genetic divergence has contributed to differential expression of multiple genes and systems during early development of these sympatric Arctic charr morphs.he project was funded by The Icelandic Center for Research (grant number: 100204011) to Sigurður S. Snorrason, Arnar Pálsson, Zophonías O. Jónsson and Bjarni K. Kristjánsson. The University of Iceland Doctoral Fund to Jóhannes Guðbrandsson and University of Iceland research fund to Arnar Pálsson, Sigurður S. Snorrason and Zophonías O. Jónsson. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer Reviewe
Differential expression of the aryl hydrocarbon receptor pathway associates with craniofacial polymorphism in sympatric Arctic charr
Background
The developmental basis of craniofacial morphology hinges on interactions of numerous signalling systems. Extensive craniofacial variation in the polymorphic Arctic charr, a member of the salmonid family, from Lake Thingvallavatn (Iceland), offers opportunities to find and study such signalling pathways and their key regulators, thereby shedding light on the developmental pathways, and the genetics of trophic divergence.
Results
To identify genes involved in the craniofacial differences between benthic and limnetic Arctic charr, we used transcriptome data from different morphs, spanning early development, together with data on craniofacial expression patterns and skeletogenesis in model vertebrate species. Out of 20 genes identified, 7 showed lower gene expression in benthic than in limnetic charr morphs. We had previously identified a conserved gene network involved in extracellular matrix (ECM) organization and skeletogenesis, showing higher expression in developing craniofacial elements of benthic than in limnetic Arctic charr morphs. The present study adds a second set of genes constituting an expanded gene network with strong, benthic–limnetic differential expression. To identify putative upstream regulators, we performed knowledge-based motif enrichment analyses on the regulatory sequences of the identified genes which yielded potential binding sites for a set of known transcription factors (TFs). Of the 8 TFs that we examined using qPCR, two (Ahr2b and Ap2) were found to be differentially expressed between benthic and limnetic charr. Expression analysis of several known AhR targets indicated higher activity of the AhR pathway during craniofacial development in benthic charr morphotypes.
Conclusion
These results suggest a key role of the aryl hydrocarbon receptor (AhR) pathway in the observed craniofacial differences between distinct charr morphotypes.This project was supported by The Icelandic Centre for Research (RANNIS/IRF, Grant 100204), The University of Iceland Research Fund and the Eimskip University Fund.Peer Reviewe
Extensive genetic differentiation between recently evolved sympatric Arctic charr morphs
Publisher's version (útgefin grein)The availability of diverse ecological niches can promote adaptation of trophic specializations and related traits, as has been repeatedly observed in evolutionary radiations of freshwater fish. The role of genetics, environment, and history in ecologically driven divergence and adaptation, can be studied on adaptive radiations or populations showing ecological polymorphism. Salmonids, especially the Salvelinus genus, are renowned for both phenotypic diversity and polymorphism. Arctic charr (Salvelinus alpinus) invaded Icelandic streams during the glacial retreat (about 10,000 years ago) and exhibits many instances of sympatric polymorphism. Particularly, well studied are the four morphs in Lake Þingvallavatn in Iceland. The small benthic (SB), large benthic (LB), planktivorous (PL), and piscivorous (PI) charr differ in many regards, including size, form, and life history traits. To investigate relatedness and genomic differentiation between morphs, we identified variable sites from RNA‐sequencing data from three of those morphs and verified 22 variants in population samples. The data reveal genetic differences between the morphs, with the two benthic morphs being more similar and the PL‐charr more genetically different. The markers with high differentiation map to all linkage groups, suggesting ancient and pervasive genetic separation of these three morphs. Furthermore, GO analyses suggest differences in collagen metabolism, odontogenesis, and sensory systems between PL‐charr and the benthic morphs. Genotyping in population samples from all four morphs confirms the genetic separation and indicates that the PI‐charr are less genetically distinct than the other three morphs. The genetic separation of the other three morphs indicates certain degree of reproductive isolation. The extent of gene flow between the morphs and the nature of reproductive barriers between them remain to be elucidated.This project was supported by The Icelandic Center for Research (RANNIS
#100204011) to SSS and coworkers, The University of Iceland Doctoral
Fund to JG and University of Iceland research fund to AP, SSS and ZOJ.Peer reviewe
Transcriptional dynamics of a conserved gene expression network associated with craniofacial divergence in Arctic charr
Background
Understanding the molecular basis of craniofacial variation can provide insights into key developmental mechanisms of adaptive changes and their role in trophic divergence and speciation. Arctic charr (Salvelinus alpinus) is a polymorphic fish species, and, in Lake Thingvallavatn in Iceland, four sympatric morphs have evolved distinct craniofacial structures. We conducted a gene expression study on candidates from a conserved gene coexpression network, focusing on the development of craniofacial elements in embryos of two contrasting Arctic charr morphotypes (benthic and limnetic).
Results
Four Arctic charr morphs were studied: one limnetic and two benthic morphs from Lake Thingvallavatn and a limnetic reference aquaculture morph. The presence of morphological differences at developmental stages before the onset of feeding was verified by morphometric analysis. Following up on our previous findings that Mmp2 and Sparc were differentially expressed between morphotypes, we identified a network of genes with conserved coexpression across diverse vertebrate species. A comparative expression study of candidates from this network in developing heads of the four Arctic charr morphs verified the coexpression relationship of these genes and revealed distinct transcriptional dynamics strongly correlated with contrasting craniofacial morphologies (benthic versus limnetic). A literature review and Gene Ontology analysis indicated that a significant proportion of the network genes play a role in extracellular matrix organization and skeletogenesis, and motif enrichment analysis of conserved noncoding regions of network candidates predicted a handful of transcription factors, including Ap1 and Ets2, as potential regulators of the gene network. The expression of Ets2 itself was also found to associate with network gene expression. Genes linked to glucocorticoid signalling were also studied, as both Mmp2 and Sparc are responsive to this pathway. Among those, several transcriptional targets and upstream regulators showed differential expression between the contrasting morphotypes. Interestingly, although selected network genes showed overlapping expression patterns in situ and no morph differences, Timp2 expression patterns differed between morphs.
Conclusion
Our comparative study of transcriptional dynamics in divergent craniofacial morphologies of Arctic charr revealed a conserved network of coexpressed genes sharing functional roles in structural morphogenesis. We also implicate transcriptional regulators of the network as targets for future functional studies.This project was supported by The Icelandic Centre for Research (RANNIS/IRF, grant 100204) and The University of Iceland Research Fund.Peer Reviewe
A prospective randomized study comparing electrochemically deposited hydroxyapatite and plasma-sprayed hydroxyapatite on titanium stems: 55 hips followed for 2 years with RSA and DXA
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