143 research outputs found

    Multiplexing with three-primer PCR for rapid and economical microsatellite validation

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    The next generation sequencing revolution has enabled rapid discovery of genetic markers, however, development of fully functioning new markers still requires a long and costly process of marker validation. This study reports a rapid and economical approach for the validation and deployment of polymorphic microsatellite markers obtained from a 454 pyrosequencing library of Atlantic cod, Gadus morhua, Linnaeus 1758. Primers were designed from raw reads to amplify specific amplicon size ranges, allowing effective PCR multiplexing. Multiplexing was combined with a three-primer PCR approach using four universal tails to label amplicons with separate fluorochromes. A total of 192 primer pairs were tested, resulting in 73 polymorphic markers. Of these, 55 loci were combined in six multiplex panels each containing between six and eleven markers. Variability of the loci was assessed on G. morhua from the Celtic Sea (n = 46) and the Scotian Shelf (n = 46), two locations that have shown genetic differentiation in previous studies. Multilocus FST between the two samples was estimated at 0.067 (P = 0.001). After three loci potentially under selection were excluded, the global FST was estimated at 0.043 (P = 0.001). Our technique combines three-primer and multiplex PCR techniques, allowing simultaneous screening and validation of relatively large numbers of microsatellite loci

    Potential Impact of Mediterranean Aquaculture on the Wild Predatory Bluefish

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    Aquaculture impacts on wild populations of fish have been considered principally due to farm escapes. The Bluefish Pomatomus saltatrix, which exhibits two distinct genetic units in the Mediterranean Sea, is a voracious predator and is attracted to aquaculture cages to prey on farmed fish, particularly Gilthead Seabream Sparus aurata and European Sea Bass Dicentrarchus labrax. We compared the genetic diversity of adult Bluefish caught inside one aquaculture farm located in Spanish waters of the western Mediterranean Sea with reference individuals of East and West Mediterranean stocks from the open sea. Bluefish were genetically assigned to their putative origin using seven microsatellite loci and mitochondrial cytochrome oxidase subunit I as molecular markers. As expected, most of the individuals caught from inside the fish farm cages were assigned to the local genetic population. However, between 7.14% and 11.9% of individuals were assigned to the distant and different genetic unit inhabiting Turkish waters, the East Mediterranean stock. The genetic membership of those individuals revealed some degree of interbreeding between the East and West Mediterranean Bluefish stocks. All results suggest that aquaculture acts as an attractor for Bluefish and could affect genetic diversity as well as phylogeography of this fish and maybe other similar species that aggregate around marine fish farms.We are very grateful to T. Ceyhan for providing the Bluefish samples from Turkey. The study was supported by the MICINN CGL-2009-08279 Grant (Spain) and the Asturian Grant GRUPIN2014-093. Laura Miralles held a PCTI Grant from the Asturias Regional Government, referenced BP 10-004. This is a contribution from the Marine Observatory of Asturias

    Who Feels Disadvantaged? Reporting Discrimination in Surveys

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    In this chapter, we seek to shed light on the mechanisms of perceived discrimination: Who, among recent immigrants, is more likely to feel discriminated against and report it when asked in a survey? Social scientists typically define discrimination as an observable and unjust difference in the treatment of distinct groups. To personally feel discriminated against, people must be aware of the differential treatment and perceive it as unjust. We show that reporting discrimination when asked in a survey depends substantially upon individual traits, including aspects that shape whether discrimination is accepted and whether immigrants feel attached to the host society. Although respondents report less discrimination if their job situation has improved after migration, people more likely report discrimination when they originate from countries in which the national legislature represents ethnic minority groups relatively well. Earlier difficulties related to the migration process and the lack of supporting networks continue to affect the perception of unfair treatment. Moreover, we show that individuals distinguish to a surprising degree between discrimination in and outside the work environment. For instance, when they are proficient in the local language, respondents often report discrimination in the workplace but not in a public environment. This distinction between discrimination in the workplace and discrimination in public also depends strongly upon the immigrant's origin. We conclude that contemporary individual-level measures and policy recommendations merely approximate discriminatory patterns; we urge future research to consider factors that affect individual perception of discrimination

    Where the Lake Meets the Sea: Strong Reproductive Isolation Is Associated with Adaptive Divergence between Lake Resident and Anadromous Three-Spined Sticklebacks

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    Contact zones between divergent forms of the same species are often characterised by high levels of phenotypic diversity over small geographic distances. What processes are involved in generating such high phenotypic diversity? One possibility is that introgression and recombination between divergent forms in contact zones results in greater phenotypic and genetic polymorphism. Alternatively, strong reproductive isolation between forms may maintain distinct phenotypes, preventing homogenisation by gene flow. Contact zones between divergent freshwater-resident and anadromous stickleback (Gasterosteus aculeatus L.) forms are numerous and common throughout the species distribution, offering an opportunity to examine these contrasting hypotheses in greater detail. This study reports on an interesting new contact zone located in a tidally influenced lake catchment in western Ireland, characterised by high polymorphism for lateral plate phenotypes. Using neutral and QTL-linked microsatellite markers, we tested whether the high diversity observed in this contact zone arose as a result of introgression or reproductive isolation between divergent forms: we found strong support for the latter hypothesis. Three phenotypic and genetic clusters were identified, consistent with two divergent resident forms and a distinct anadromous completely plated population that migrates in and out of the system. Given the strong neutral differentiation detected between all three morphotypes (mean F-ST = 0.12), we hypothesised that divergent selection between forms maintains reproductive isolation. We found a correlation between neutral genetic and adaptive genetic differentiation that support this. While strong associations between QTL linked markers and phenotypes were also observed in this wild population, our results support the suggestion that such associations may be more complex in some Atlantic populations compared to those in the Pacific. These findings provide an important foundation for future work investigating the dynamics of gene flow and adaptive divergence in this newly discovered stickleback contact zone

    Policy and Practice in Language Support for Newly Arrived Migrant Children in Ireland and Spain

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    To cite this article: Rosa M Rodríguez-Izquierdo & Merike Darmody (2017): Policy and Practice in Language Support for Newly Arrived Migrant Children in Ireland and Spain, British Journal of Educational Studies, DOI: 10.1080/00071005.2017.1417973Over the last decades migration across Europe has continued to increase. Consequently, the issue of offering appropriate educational support for migrant students has been extensively debated across Europe and further afield, especially in countries with a history of immigration. However, less is known about how education systems in the ¿new¿ immigration countries have responded to the needs of newly arrived migrants (NAMs). While various research and policy documents have highlighted the importance of proficiency in the language of instruction for social and academic outcomes of migrant children and youth: how language support is provided varies significantly from one jurisdiction to another. This article focuses on language support measures set up for migrant students in statefunded schools in the Republic of Ireland and Spain ¿ both multilingual countries with more than one official language and with heterogeneous migrant population. In both countries, there is also a mismatch between an increasingly diverse student cohort and a homogenous teacher population.. Reviewing educational policy and practice in these jurisdictions in the areas of language support for migrants and how diversity is addressed in initial teacher education, the paper seeks to contribute to the debate on how to address the needs of migrant students in multi-lingual settings.Educación y Psicología SocialPreprin

    Comparing the transcriptomes of embryos from domesticated and wild Atlantic salmon (Salmo salar L.) stocks and examining factors that influence heritability of gene expression

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    Background  Due to selective breeding, domesticated and wild Atlantic salmon are genetically diverged, which raises concerns about farmed escapees having the potential to alter the genetic composition of wild populations and thereby disrupting local adaptation. Documenting transcriptional differences between wild and domesticated stocks under controlled conditions is one way to explore the consequences of domestication and selection. We compared the transcriptomes of wild and domesticated Atlantic salmon embryos, by using a custom 44k oligonucleotide microarray to identify perturbed gene pathways between the two stocks, and to document the inheritance patterns of differentially-expressed genes by examining gene expression in their reciprocal hybrids.  Results  Data from 24 array interrogations were analysed: four reciprocal cross types (W♀×W♂, D♀×W♂; W♀×D♂, D♀×D♂)×six biological replicates. A common set of 31,491 features on the microarrays passed quality control, of which about 62% were assigned a KEGG Orthology number. A total of 6037 distinct genes were identified for gene-set enrichment/pathway analysis. The most highly enriched functional groups that were perturbed between the two stocks were cellular signalling and immune system, ribosome and RNA transport, and focal adhesion and gap junction pathways, relating to cell communication and cell adhesion molecules. Most transcripts that were differentially expressed between the stocks were governed by additive gene interaction (33 to 42%). Maternal dominance and over-dominance were also prevalent modes of inheritance, with no convincing evidence for a stock effect.  Conclusions  Our data indicate that even at this relatively early developmental stage, transcriptional differences exist between the two stocks and affect pathways that are relevant to wild versus domesticated environments. Many of the identified differentially perturbed pathways are involved in organogenesis, which is expected to be an active process at the eyed egg stage. The dominant effects are more largely due to the maternal line than to the origin of the stock. This finding is particularly relevant in the context of potential introgression between farmed and wild fish, since female escapees tend to have a higher spawning success rate compared to males

    Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

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    Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability
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