6 research outputs found

    Molecular genetic evidence for mixed maternity in broods of the Coal Tit Parus ater

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    Mittels molekulargenetischer Elternschaftsanalyse wurde eine niedrige Rate gemischter Mutterschaften in Bruten der sozial monogamen Tannenmeise nachgewiesen, einer Art, die sich durch hohe Fremdvaterschaftsraten auszeichnet. Gemischte Mutterschaften wurden in vier (= 0,8 %) von 483 Bruten entdeckt und nur für zehn (= 0,3 %) von 3563 erfolgreich genotypisierten Nachkommen wurde die Putativmutter von der genetischen Mutterschaft ausgeschlossen. In Anbetracht dieser sehr niedrigen Rate kann in evolutionsbiologischen Studien der soziale Fortpflanzungserfolg mit dem genetischen Fortpflanzungserfolg für Weibchen der Tannenmeise ohne weiteres gleichgesetzt werden. Die Putativväter wurden ebenfalls in allen Fällen von der genetischen Elternschaft ausgeschlossen, was Quasiparasitismus als Erklärung für gemischte Mutterschaften ausschließt. In einem Fall konnten die Partner eines Brutpaares, das zeitgleich in der Nähe eine eigene Brut aufzog, zweifelsfrei als die genetischen Eltern eines einzelnen Nachkommen identifiziert werden. Mögliche Ursachen für das Auftreten gemischter Mutterschaften bei der Tannenmeise schließen die Übernahme von Nistkästen samt begonnenen Gelegen nach dem Tod oder Abwandern der Vorbesitzer und innerartlichen Brutparasitismus ein.Molecular genetic analysis of parentage revealed a low frequency of mixed maternity in broods of the Coal Tit, a socially monogamous passerine with a high frequency of extra-pair paternity. Mixed maternity was detected in four (= 0.8 %) out of 483 analysed broods. For ten (= 0.3 %) out of 3563 successfully genotyped offspring the attending putative (social) mother was excluded from genetic parentage. Given the very low frequency of mixed maternity, social reproductive success can conveniently be equated with genetic reproductive success for female Coal Tits in evolutionary studies. Attending putative fathers were excluded from genetic parentage in all cases, too, ruling out quasi-parasitism as a mechanistic explanation for mixed maternity. In one case, the pair members from an adjacent territory were unequivocally identified as the genetic parents of a single offspring (they were simultaneously attending their own brood). Possible mechanisms leading to mixed maternity broods in the Coal Tit may include nest/clutch take-over and intraspecific brood parasitism and their respective relevance is briefly discussed

    How Individualized Niches Arise: Mechanisms of Niche Construction, Niche Choice, and Niche Conformance

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    Trappes R, Nematipour B, Kaiser MI, et al. How Individualized Niches Arise: Mechanisms of Niche Construction, Niche Choice, and Niche Conformance. EcoEvoRxiv. 2021

    The politics of culture in Northern Ireland

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    OBJECTIVES: The first consensus report that had been presented by the European Germ Cell Cancer Consensus Group (EGCCCG) in 2004 has found widespread approval by many colleagues throughout the world. In November 2006, the group met a second time under the auspices of the Department of Urology of the Amsterdam Medical Center, The Netherlands. METHODS: Medical oncologists, urologic surgeons, radiation oncologists as well as pathologists from several European countries reviewed and discussed the data that had emerged since the 2002 conference and incorporated the new data into updated and revised guidelines. As for the first meeting the methodology of evidence-based medicine (EBM) was applied. The results of the discussion were compiled by the writing committee. All participants have agreed to this final update. RESULTS: The second part of the consensus paper includes the treatment of metastasised disease, residual tumour resection, salvage therapy, follow-up, and late toxicities. CONCLUSIONS: Whereas the vast majority of the recommendations made in 2004 remain valid 3 yr later, refinements in the treatment of early-stage as well as of advanced-stage testicular cancer have emerged from clinical trials. Despite technical improvements, expert clinical skills will continue to be one of the major determinants for the prognosis of patients with germ cell cancer. In addition, the particular needs of testicular cancer survivors have been acknowledged

    Same data, different analysts: variation in effect sizes due to analytical decisions in ecology and evolutionary biology

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    Gould E, Fraser H, Parker T, et al. Same data, different analysts: variation in effect sizes due to analytical decisions in ecology and evolutionary biology. 2023.Although variation in effect sizes and predicted values among studies of similar phenomena is inevitable, such variation far exceeds what might be produced by sampling error alone. One possible explanation for variation among results is differences among researchers in the decisions they make regarding statistical analyses. A growing array of studies has explored this analytical variability in different (mostly social science) fields, and has found substantial variability among results, despite analysts having the same data and research question. We implemented an analogous study in ecology and evolutionary biology, fields in which there have been no empirical exploration of the variation in effect sizes or model predictions generated by the analytical decisions of different researchers. We used two unpublished datasets, one from evolutionary ecology (blue tit, Cyanistes caeruleus, to compare sibling number and nestling growth) and one from conservation ecology (Eucalyptus, to compare grass cover and tree seedling recruitment), and the project leaders recruited 174 analyst teams, comprising 246 analysts, to investigate the answers to prespecified research questions. Analyses conducted by these teams yielded 141 usable effects for the blue tit dataset, and 85 usable effects for the Eucalyptus dataset. We found substantial heterogeneity among results for both datasets, although the patterns of variation differed between them. For the blue tit analyses, the average effect was convincingly negative, with less growth for nestlings living with more siblings, but there was near continuous variation in effect size from large negative effects to effects near zero, and even effects crossing the traditional threshold of statistical significance in the opposite direction. In contrast, the average relationship between grass cover and Eucalyptus seedling number was only slightly negative and not convincingly different from zero, and most effects ranged from weakly negative to weakly positive, with about a third of effects crossing the traditional threshold of significance in one direction or the other. However, there were also several striking outliers in the Eucalyptus dataset, with effects far from zero. For both datasets, we found substantial variation in the variable selection and random effects structures among analyses, as well as in the ratings of the analytical methods by peer reviewers, but we found no strong relationship between any of these and deviation from the meta-analytic mean. In other words, analyses with results that were far from the mean were no more or less likely to have dissimilar variable sets, use random effects in their models, or receive poor peer reviews than those analyses that found results that were close to the mean. The existence of substantial variability among analysis outcomes raises important questions about how ecologists and evolutionary biologists should interpret published results, and how they should conduct analyses in the future

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