206 research outputs found

    Genetic Adaptation in Relation to Animal Welfare

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    The author outlines the adaptation processes of animals and animal populations and discusses their relevance to the animal welfare problem. Because animal welfare has many different aspects, including philosophical, ethical, and biological, it is important to examine some fundamental issues underlying the concept. Hence, in this essay, the author comments on how people come to know, how information accumulates, and how what we know influences our actions. The author also discusses the biological information that is relevant to animal welfare. When this topic has been placed within a broader framework, more generally useful solutions to the animal welfare problem may be found

    Genetic Adaptation in Relation to Animal Welfare

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    In this essay I outline the processes of adaptation of animals and of animal populations and discuss their relevance to the problem of animal welfare. Because animal welfare has many different aspects including philosophical, ethical, and biological, it is important to examine some of the fundamental issues that underly the concept. Hence, in this essay, I comment on how people come to know, how information accumulates, and how what we know influences our actions. I also discuss the biological information that is relevant to animal welfare. It is my hope that, when this topic has been placed within a broader framework of this sort, more generally useful solutions to the animal welfare problem may be found

    Effects of Selection for High Litter-Weight on Reproductive Performance in Mice.

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    The reproductive performances of two lines of mice selected for high litter-weight at nine weeks of age and a control line were compared based on data obtained after 15 generations of breeding. Twenty pairs of parents were bred per generation in the control line and ten pairs in each of the selected lines: at each generation the parents were mated only once. Calculation of inbreeding coefficients from pedigrees indicated a rapid rise in inbreeding coefficient in the selected lines. There was little response to selection for high litter-weight and in fact there was a general decline in reproductive performance associated with high levels of inbreeding in the selected lines although the relationship was not linear. Some initial response tn body weight gain was observed but even this trait showed a decline in later generations when inbreeding coefficient exceeded 40%

    Contextual factors among indiscriminate or larger attacks on food or water supplies, 1946-2015

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    This research updates previous inventories of malicious attacks on food and water to include data from 1946 through mid-2015. A systematic search of news reports, databases and previous inventories of poisoning events was undertaken. Incidents that threatened or were intended to achieve direct harm to humans, and that were either relatively large (number of victims > 4 or indiscriminate in intent or realisation were included. Agents could be chemical, biological or radio-nuclear. Reports of candidate incidents were subjected to systematic inclusion and exclusion criteria as well as validity analysis (not always clearly undertaken in previous inventories of such attacks). We summarise contextual aspects of the attacks that may be important for scenario prioritisation, modelling and defensive preparedness. Opportunity is key to most realised attacks, particularly access to dangerous agents. The most common motives and relative success rate in causing harm were very different between food and water attacks. The likelihood that people were made ill or died also varied by food/water mode, and according to motive and opportunity for delivery of the hazardous agent. Deaths and illness associated with attacks during food manufacture and prior to sale have been fewer than those in some other contexts. Valuable opportunities for food defence improvements are identified in other contexts, especially food prepared in private or community settings

    microRNA-Mediated Messenger RNA Deadenylation Contributes to Translational Repression in Mammalian Cells

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    Animal microRNAs (miRNAs) typically regulate gene expression by binding to partially complementary target sites in the 3′ untranslated region (UTR) of messenger RNA (mRNA) reducing its translation and stability. They also commonly induce shortening of the mRNA 3′ poly(A) tail, which contributes to their mRNA decay promoting function. The relationship between miRNA-mediated deadenylation and translational repression has been less clear. Using transfection of reporter constructs carrying three imperfectly matching let-7 target sites in the 3′ UTR into mammalian cells we observe rapid target mRNA deadenylation that precedes measureable translational repression by endogenous let-7 miRNA. Depleting cells of the argonaute co-factors RCK or TNRC6A can impair let-7-mediated repression despite ongoing mRNA deadenylation, indicating that deadenylation alone is not sufficient to effect full repression. Nevertheless, the magnitude of translational repression by let-7 is diminished when the target reporter lacks a poly(A) tail. Employing an antisense strategy to block deadenylation of target mRNA with poly(A) tail also partially impairs translational repression. On the one hand, these experiments confirm that tail removal by deadenylation is not strictly required for translational repression. On the other hand they show directly that deadenylation can augment miRNA-mediated translational repression in mammalian cells beyond stimulating mRNA decay. Taken together with published work, these results suggest a dual role of deadenylation in miRNA function: it contributes to translational repression as well as mRNA decay and is thus critically involved in establishing the quantitatively appropriate physiological response to miRNAs

    microRNA input into a neural ultradian oscillator controls emergence and timing of alternative cell states.

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    © 2014 Macmillan Publishers LimitedThis is an open access article that is freely available in ORE or from the publisher's web site. Please cite the published version.Progenitor maintenance, timed differentiation and the potential to enter quiescence are three fundamental processes that underlie the development of any organ system. In the nervous system, progenitor cells show short-period oscillations in the expression of the transcriptional repressor Hes1, while neurons and quiescent progenitors show stable low and high levels of Hes1, respectively. Here we use experimental data to develop a mathematical model of the double-negative interaction between Hes1 and a microRNA, miR-9, with the aim of understanding how cells transition from one state to another. We show that the input of miR-9 into the Hes1 oscillator tunes its oscillatory dynamics, and endows the system with bistability and the ability to measure time to differentiation. Our results suggest that a relatively simple and widespread network of cross-repressive interactions provides a unifying framework for progenitor maintenance, the timing of differentiation and the emergence of alternative cell states.Wellcome Trus

    Seamless Gene Tagging by Endonuclease-Driven Homologous Recombination

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    Gene tagging facilitates systematic genomic and proteomic analyses but chromosomal tagging typically disrupts gene regulatory sequences. Here we describe a seamless gene tagging approach that preserves endogenous gene regulation and is potentially applicable in any species with efficient DNA double-strand break repair by homologous recombination. We implement seamless tagging in Saccharomyces cerevisiae and demonstrate its application for protein tagging while preserving simultaneously upstream and downstream gene regulatory elements. Seamless tagging is compatible with high-throughput strain construction using synthetic genetic arrays (SGA), enables functional analysis of transcription antisense to open reading frames and should facilitate systematic and minimally-invasive analysis of gene functions

    Comparison of gene expression during in vivo and in vitro postnatal retina development

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    Retina explants are widely used as a model of neural development. To define the molecular basis of differences between the development of retina in vivo and in vitro during the early postnatal period, we carried out a series of microarray comparisons using mouse retinas. About 75% of 8,880 expressed genes from retina explants kept the same expression volume and pattern as the retina in vivo. Fewer than 6% of the total gene population was changed at two consecutive time points, and only about 1% genes showed more than a threefold change at any time point studied. Functional Gene Ontology (GO) mapping for both changed and unchanged genes showed similar distribution patterns, except that more genes were changed in the GO clusters of response to stimuli and carbohydrate metabolism. Three distinct expression patterns of genes preferentially expressed in rod photoreceptors were observed in the retina explants. Some genes showed a lag in increased expression, some showed no change, and some continued to have a reduced level of expression. An early downregulation of cyclin D1 in the explanted retina might explain the reduction in numbers of precursors in explanted retina and suggests that external factors are required for maintenance of cyclin D1. The global view of gene profiles presented in this study will help define the molecular changes in retina explants over time and will provide criteria to define future changes that improve this model system
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