9 research outputs found

    The great tit HapMap project: a continental‐scale analysis of genomic variation in a songbird

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    A major aim of evolutionary biology is to understand why patterns of genomic diversity vary within taxa and space. Large-scale genomic studies of widespread species are useful for studying how environment and demography shape patterns of genomic divergence. Here, we describe one of the most geographically comprehensive surveys of genomic variation in a wild vertebrate to date; the great tit (Parus major) HapMap project. We screened ca 500,000 SNP markers across 647 individuals from 29 populations, spanning ~30 degrees of latitude and 40 degrees of longitude – almost the entire geographical range of the European subspecies. Genome-wide variation was consistent with a recent colonisation across Europe from a South-East European refugium, with bottlenecks and reduced genetic diversity in island populations. Differentiation across the genome was highly heterogeneous, with clear ‘islands of differentiation’, even among populations with very low levels of genome-wide differentiation. Low local recombination rates were a strong predictor of high local genomic differentiation (FST), especially in island and peripheral mainland populations, suggesting that the interplay between genetic drift and recombination causes highly heterogeneous differentiation landscapes. We also detected genomic outlier regions that were confined to one or more peripheral great tit populations, probably as a result of recent directional selection at the species' range edges. Haplotype-based measures of selection were related to recombination rate, albeit less strongly, and highlighted population-specific sweeps that likely resulted from positive selection. Our study highlights how comprehensive screens of genomic variation in wild organisms can provide unique insights into spatio-temporal evolutionary dynamics

    Propyl gallate-induced platelet aggregation in patients with end-stage renal disease: The influence of the haemodialysis procedure

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    Background: Platelet dysfunction is a well-established disturbance in haemodialysis (HD) patients. Propyl gallate is a synthetic platelet activator with the property to stimulate platelet aggregation. The aim of the present study was to evaluate the influence of a single haemodialysis session on propyl gallate-induced platelet aggregation. Methods: Thirty-nine HD patients were enrolled in the study and 20 healthy volunteers were studied as controls. Cellulose diacetate (CD) dialysers were used in 20 patients and polysulphone dialysers in 19. HD was performed via an A-V fistula in 27 patients and via an i.v. catheter in 12. Erythropoietin was administered in 37 patients (epoietin-alpha in 24 and darbepoietin in 13). Thirty-four were receiving the low-molecular-weight heparin tinzaparin. Propyl gallate slide aggregometry was used for evaluating platelet aggregation. Results: In HD patients, platelet aggregation was impaired before as well as after the HD session. No effect of the HD procedure, type of vascular access, adequacy of HD or type of erythropoietin on the propyl gallate-induced platelet aggregation was detected. Platelet aggregation was higher when CD dialyser was used. A negative correlation between the time needed for platelet aggregation to occur and tinzaparin dose was found. Conclusion: Propyl gallate-induced platelet aggregation in HD patients is impaired. Platelet aggregation was higher in patients dialysed with CD membrane than in those dialysed with polysulphone membrane. The higher the dose of tinzaparin, the higher the platelet aggregation. The clinical significance of the above results needs further evaluation

    Tracking data highlight the importance of human-induced mortality for large migratory birds at a flyway scale

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    Human-induced direct mortality affects huge numbers of birds each year, threatening hundreds of species worldwide. Tracking technologies can be an important tool to investigate temporal and spatial patterns of bird mortality as well as their drivers. We compiled 1704 mortality records from tracking studies across the African-Eurasian flyway for 45 species, including raptors, storks, and cranes, covering the period from 2003 to 2021. Our results show a higher frequency of human-induced causes of mortality than natural causes across taxonomic groups, geographical areas, and age classes. Moreover, we found that the frequency of human-induced mortality remained stable over the study period. From the human-induced mortality events with a known cause (n = 637), three main causes were identified: electrocution (40.5 %), illegal killing (21.7 %), and poisoning (16.3 %). Additionally, combined energy infrastructure-related mortality (i.e., electrocution, power line collision, and wind-farm collision) represented 49 % of all human-induced mortality events. Using a random forest model, the main predictors of human-induced mortality were found to be taxonomic group, geographic location (latitude and longitude), and human footprint index value at the location of mortality. Despite conservation efforts, human drivers of bird mortality in the African-Eurasian flyway do not appear to have declined over the last 15 years for the studied group of species. Results suggest that stronger conservation actions to address these threats across the flyway can reduce their impacts on species. In particular, projected future development of energy infrastructure is a representative example where application of planning, operation, and mitigation measures can enhance bird conservation.publishedVersio
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