A genetic linkage map for the saltwater crocodile (Crocodylus porosus)

<p>Abstract</p> <p>Background</p> <p>Genome elucidation is now in high gear for many organisms, and whilst genetic maps have been developed for a broad array of species, surprisingly, no such maps exist for a crocodilian, or indeed any other non-avian member of the Class Reptilia. Genetic linkage maps are essential tools for the mapping and dissection of complex quantitative trait loci (QTL), and in order to permit systematic genome scans for the identification of genes affecting economically important traits in farmed crocodilians, a comprehensive genetic linage map will be necessary.</p> <p>Results</p> <p>A first-generation genetic linkage map for the saltwater crocodile (<it>Crocodylus porosus</it>) was constructed using 203 microsatellite markers amplified across a two-generation pedigree comprising ten full-sib families from a commercial population at Darwin Crocodile Farm, Northern Territory, Australia. Linkage analyses identified fourteen linkage groups comprising a total of 180 loci, with 23 loci remaining unlinked. Markers were ordered within linkage groups employing a heuristic approach using CRIMAP v3.0 software. The estimated female and male recombination map lengths were 1824.1 and 319.0 centimorgans (cM) respectively, revealing an uncommonly large disparity in recombination map lengths between sexes (ratio of 5.7:1).</p> <p>Conclusion</p> <p>We have generated the first genetic linkage map for a crocodilian, or indeed any other non-avian reptile. The uncommonly large disparity in recombination map lengths confirms previous preliminary evidence of major differences in sex-specific recombination rates in a species that exhibits temperature-dependent sex determination (TSD). However, at this point the reason for this disparity in saltwater crocodiles remains unclear.</p> <p>This map will be a valuable resource for crocodilian researchers, facilitating the systematic genome scans necessary for identifying genes affecting complex traits of economic importance in the crocodile industry. In addition, since many of the markers placed on this genetic map have been evaluated in up to 18 other extant species of crocodilian, this map will be of intrinsic value to comparative mapping efforts aimed at understanding genome content and organization among crocodilians, as well as the molecular evolution of reptilian and other amniote genomes. As researchers continue to work towards elucidation of the crocodilian genome, this first generation map lays the groundwork for more detailed mapping investigations, as well as providing a valuable scaffold for future genome sequence assembly.</p

Sequencing three crocodilian genomes to illuminate the evolution of archosaurs and amniotes

The International Crocodilian Genomes Working Group (ICGWG) will sequence and assemble the American alligator (Alligator mississippiensis), saltwater crocodile (Crocodylus porosus) and Indian gharial (Gavialis gangeticus) genomes. The status of these projects and our planned analyses are described

The Moon among Stars and The Throne in the Forest : Image and formula in the \u27Nibelungenlied\u27 and the \u27Ramayana\u27

THESIS 6757The point of reference in earlier comparative studies of epic featuring either the medieval German Nibelungenlied or the ancient Indian Ramayana as one component of the comparison has been narrative content, narrative technique and/or structure. To my knowledge this is the first study not only to combine the two poems in question but also to make a text-based examination of imagery rather than narratology the basis of a comparative study of epic. The absence of an intertextual link between the two works makes the analogies more remarkable, but the methodology used takes note both of homologies and of disparities, since it is difference as much as similarity which broadens knowledge about the nature of the epic genre. Having outlined the ongoing debate on oral and written narrative poetry, especially with reference to formulaic expression and the opposing theories of \u27composition in performance\u27 and \u27verbatim memorisation\u27, this study proceeds to discuss the internal, and, where possible, external evidence indicating the oral composition and aural reception of the Nibelungenlied and the Ramayana. Then follows a general consideration of the poetic image in concept and in practice, drawing in part on prescriptive material found in each tradition and making frequent use of illustrative examples from the Nibelungenlied and the Ramayana. It establishes definitions of the terms which will be used to distinguish between the two types of imagery to be explored in this thesis, namely a) the poetic image as figure of speech and b) the poetic image as symbol. Building on these definitions, the study proceeds to textual examination of examples of stock simile common to the texts and to suggest possible functions of formulaic imagery in the compositional dynamics of the epics. A comparative analysis of symbolic images of sovereignty follows. The imagery centres around the formulaic diametrically opposite symbols of the City, the centre of socio-political structures, and the mythical Forest (the location of the metaphorical throne of the thesis title) which is at the same time both the negation and the validation of these structures, and thirdly the City which lies within the Forest and contains elements of both City and Forest. This contextual investigation leads to an assessment of the function of these three types of symbols in portraying the kingship of Siegfried and Rama: what these symbols tell us specifically about the similarities and differences in their nature and rule

Socio-economic and food system drivers of nutrition and health transitions in The Gambia from 1990 to 2017

In common with many nations undergoing a nutrition transition, micronutrient deficiencies, undernutrition and overnutrition coexist in The Gambia. Addressing these challenges simultaneously would require transformational changes in the country's food system. However, the evidence base that would enable informed decision-making in the Gambian food system has been scant, despite several sources of routinely-collected data being available. This descriptive study brings together data from four open-access global databases on food supply, political, economic, and demographic variables, and nutrition and health between 1990 and 2017 to study potential leverage points for improvement in the food system. It compares trends in food supply and nutritional outcomes in The Gambia against regional and global averages, and identifies potential drivers taken from a food systems framework. The data show that, over the past three decades, total energy supply has increased, and obesity is rising quickly, but iron deficiency persists in a proportion of the population. Overall diet composition is poor, with lower availability of fruit and vegetables and higher supply of sugar and oils compared to regional and global averages. Domestic production is low for most food groups and so a high dependence on imports from other countries bridges the gap in terms of energy supply. Measures of economic development, particularly GDP, were positively related with supply of cereals and animal source foods over time, but no such relationship was observed with fruit and vegetable supply. Food system policy to improve nutrition and health outcomes in The Gambia needs to focus on improving the diversity of food supply – especially fruit and vegetables - and maximizing national domestic production to reduce reliance on food imports. The use of open-source global datasets can be feasible in exploring food system characteristics and trends at the national level and could be applied in other contexts