60 research outputs found

    Adaptive venom evolution and toxicity in octopods is driven by extensive novel gene formation, expansion, and loss

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    Background: Cephalopods represent a rich system for investigating the genetic basis underlying organismal novelties. This diverse group of specialized predators has evolved many adaptations including proteinaceous venom. Of particular interest is the blue-ringed octopus genus (Hapalochlaena), which are the only octopods known to store large quantities of the potent neurotoxin, tetrodotoxin, within their tissues and venom gland. Findings: To reveal genomic correlates of organismal novelties, we conducted a comparative study of 3 octopod genomes, including the Southern blue-ringed octopus (Hapalochlaena maculosa). We present the genome of this species and reveal highly dynamic evolutionary patterns at both non-coding and coding organizational levels. Gene family expansions previously reported in Octopus bimaculoides (e.g., zinc finger and cadherins, both associated with neural functions), as well as formation of novel gene families, dominate the genomic landscape in all octopods. Examination of tissue-specific genes in the posterior salivary gland revealed that expression was dominated by serine proteases in non–tetrodotoxin-bearing octopods, while this family was a minor component in H. maculosa. Moreover, voltage-gated sodium channels in H. maculosa contain a resistance mutation found in pufferfish and garter snakes, which is exclusive to the genus. Analysis of the posterior salivary gland microbiome revealed a diverse array of bacterial species, including genera that can produce tetrodotoxin, suggestive of a possible production source. Conclusions: We present the first tetrodotoxin-bearing octopod genome H. maculosa, which displays lineage-specific adaptations to tetrodotoxin acquisition. This genome, along with other recently published cephalopod genomes, represents a valuable resource from which future work could advance our understanding of the evolution of genomic novelty in this family

    Proceedings of the workshop on national/regional energy-environmental modeling concepts, May 30-June 1, 1979

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    The purpose of the workshop was to identify and evaluate approaches to regional economic and energy supply/demand forecasting that are best suited to assisting DOE in the assessment of environmental impacts of national energy policies. Specifically the DOE Office of Technology Impacts uses models to assess the impacts of technology change; to analyze differential impacts of various energy policies; and to provide an early-warning system of possible environmental constraints to energy development. Currently, OTI employs both a top-down model system to analyze national scenarios and a bottom-up assessment conducted from a regional perspective. A central theme of the workshop was to address the problem of how OTI should integrate the top-down and bottom-up approaches. The workshop was structured to use the experience of many fields of regional analysis toward resolving that problem. For the short-term, recommendations were suggested for improving the current OTI models, but most of the comments were directed toward the development of a new methodology. It was recommended that a core set of related models be developed that are modular, dynamic and consistent: they would require an inter-industry accounting framework; inter-regional linkages; and adequate documentation. Further, it was suggested that an advisory group be formed to establish the appropriate methodological framework of the model system. With regard to data used in any policy analysis model, it was recommended that OTI develop and maintain an integrated system of economic, environmental, and energy accounts that is coordinated with the statistical agencies that collect the data
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