11 research outputs found

    Integrated Multi-Parameter Exploration Footprints of the Canadian Malartic Disseminated Au, McArthur River-Millennium Unconformity U, and Highland Valley Porphyry Cu Deposits: Preliminary Results from the NSERC-CMIC Mineral Exploration Footprints Research Network

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    Mineral exploration in Canada is increasingly focused on concealed and deeply buried targets, requiring more effective tools to detect large-scale ore-forming systems and to vector from their most distal margins to their high grade cores. A new generation of ore system models is required to achieve this. The Mineral Exploration Footprints Research Network is a consortium of 70 faculty, research associates, and students from 20 Canadian universities working with 30 mining, mineral exploration, and mining service providers to develop new approaches to ore system modelling based on more effective integration and visualization of multi-parameter geological-structural-mineralogical-lithogeochemical-petrophysical-geophysical exploration data. The Network is developing the next generation ore system models and exploration strategies at three sites based on integrated data visualization using self-consistent 3D Common Earth Models and geostatistical/machine learning technologies. Thus far over 60 footprint components and vectors have been identified at the Canadian Malartic stockwork-disseminated Au deposit, 20–30 at the McArthur-Millennium unconformity U deposits, and over 20 in the Highland Valley porphyry Cu system. For the first time, these are being assembled into comprehensive models that will serve as landmark case studies for data integration and analysis in the today’s challenging exploration environment

    Model species in evo-devo: A philosophical perspective

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    Abstract A model is a representation of or an analogy for something else; in a biological context, the term often refers to organisms or species that serve as a widely used platform for experimental research. In developmental biology, an extraordinarily detailed understanding of fundamental genes and mechanisms has been built around a few core models including Drosophila, mouse, Caenorhabditis elegans, Arabidopsis, and zebrafish. The use of model species entails a series of epistemological issues and commitments regarding similarity, generalization, and the balance between representation and accessibility. In addition, the power of a given model is highly context-dependent, and the core models of developmental biology may not suffice for evo-devo questions. An epistemological perspective can clarify the complementary roles of standard and emerging models in evo-devo, as well as inform decisions about when new models are needed, and criteria for choosing them. © 2013 Wiley Periodicals, Inc

    Data from: Genetic dissection of adaptive form and function in rapidly-speciating cichlid fishes

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    Genes of major phenotypic effects and strong genetic correlations can facilitate adaptation, direct selective responses and potentially lead to phenotypic convergence. However, the preponderance of this type of genetic architecture in repeatedly-evolved adaptations remains unknown. Using hybrids between Haplochromis chilotes (thick-lipped) and H. nyererei (thin-lipped) we investigated the genetics underlying hypertrophied lips and elongated heads, traits that evolved repeatedly in cichlids. At least 25 loci of small-to-moderate and mainly additive effects were detected. Phenotypic variation in lip and head morphology was largely independent. Although several QTL overlapped for lip and head morphology traits, they were often of opposite effects. The distribution of effect signs suggests strong selection on lips. The fitness implications of several detected loci were demonstrated using a laboratory assay testing for the association between genotype and variation in foraging performance. The persistence of low fitness alleles in head morphology appears to be maintained through antagonistic pleiotropy/close linkage with positive-effect lip morphology alleles. Rather than being based on few major loci with strong positive genetic correlations, our results indicate that the evolution of the Lake Victoria thick-lipped ecomorph is the result of selection on numerous loci distributed throughout the genome

    Multiple trans QTL and one cis-regulatory deletion are associated with the differential expression of cone opsins in African cichlids

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    Abstract Background Dissecting the genetic basis of phenotypic diversity is one of the fundamental goals in evolutionary biology. Despite growing evidence for gene expression divergence being responsible for the evolution of complex traits, knowledge about the proximate genetic causes underlying these traits is still limited. African cichlids have diverse visual systems, with different species expressing different combinations of seven cone opsin genes. Using opsin expression variation in African cichlids as a model for gene expression evolution, this study aims to investigate the genetic architecture of opsin expression divergence in this group. Results Results from a genome-wide linkage mapping on the F2 progeny of an intergeneric cross, between two species with differential opsin expression show that opsins in Lake Malawi cichlids are controlled by multiple quantitative trait loci (QTLs). Most of these QTLs are located in trans to the opsins except for one cis-QTL for SWS1 on LG17. A closer look at this major QTL revealed the presence of a 691 bp deletion in the promoter of the SWS1 opsin (located 751 bp upstream of the start site) that is associated with a decrease in its expression. Phylogenetic footprinting indicates that the region spanning the deletion harbors a microRNA miR-729 and a conserved non-coding element (CNE) that also occurs in zebrafish and other teleosts. This suggests that the deletion might contain ancestrally preserved regulators that have been tuned for SWS1 gene expression in Lake Malawi. While this deletion is not common, it does occur in several other species within the lake. Conclusions Differential expression of cichlid opsins is associated with multiple overlapping QTL, with all but one in trans to the opsins they regulate. The one cis-acting factor is a deletion in the promoter of the SWS1 opsin, suggesting that ancestral polymorphic deletions may contribute to cichlid’s visual diversity. In addition to expanding our understanding of the molecular landscape of opsin expression in African cichlids, this study sheds light on the molecular mechanisms underlying phenotypic variation in natural populations
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