1,721,234 research outputs found
Genomic and other revolutions—why some technologies are quickly adopted and others are not
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Accounting for non-independence of extinction probabilities in the derivation of conservation priorities based on Weitzman's diversity concept
No full textIn the original formulation of Weitzman's diversity concept, extinction probabilities of different operational taxonomic units (OTUs) are implicitly defined to be independent. In this study, it is shown, that dependencies like concurrence or synergistic relations between OTUs can be accounted for by assuming that joint extinction probabilities differ from the product of the extinction probabilities of the interacting OTUs. A fully analytical treatment is provided for the case of two interacting OTUs, and all cases are illustrated with an example data set. For the case of concurring OTUs, the following general results are derived: (a) concurrence between OTUs always reduces the amount of diversity expected to be conserved in the future; (b) concurrence has a more adverse effect on the more endangered OTUs involved; (c) concurrence can change conservation priorities between OTUs; and (d) with high levels of concurrence, investments in the conservation of some of the concurring OTUs can have a negative effect on the overall diversity conserved. In addition to conservation activities targeted towards some of the OTUs, reduction of the causes of concurrence may be a valid and cost-efficient alternative. For the case of synergistic dependencies between OTUs it was found, that such dependencies always increase the conservation potential of the involved OTUs but may lead to a change of priority ranking in extreme cases. Finally possible extensions and generalisations of the suggested approach are discussed and it is argued, that by adopting these extensions Weitzman's diversity concept becomes an even more powerful and flexible tool to derive conservation priorities both in an ecological and in a farm animal context
Harvest Moon: Some personal thoughts on past and future directions in animal breeding research
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Mapping signatures of positive selection in the genome of livestock
No full textHuman driven selection during domestication and subsequent breed formation and breeding has left detectable signatures within the genome of livestock breeds. The elucidation of these signatures of selection is of interest from the perspective of evolutionary biology and for identifying selected genes that ultimately may help to further genetically improve these economically important species. Genome-wide screenings based on population techniques provide analytical tools to detect these signatures in relation to the act of selection. This review outlines a nonmathematical treatment of the theories and approaches available to scan the genome for evidence of positive selection and is intended for readers who are little or not familiar with population genetics theory. We discuss the genetics underlying phenotypic variation and adaptation and highlight molecular pattern that positive selection leaves behind along with the statistical approaches that are developed to detect such signatures. We describe some of the relative strengths and weaknesses of different strategies and also the challenges with identifying signatures of selection. Ascertainment bias with widely used SNP arrays is also a topic of interest. Finally we review approaches to assess the statistical significance of a signal at a particular locus or window and discuss factors affecting the statistical power to detect selective sweeps. (C) 2014 Published by Elsevier B.V
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