Farmed fish are dependent on dietary inputs of oils (lipids) derived from wild fish. The stocks of wild fish from which these oils are derived are under increasing pressure from over-fishing and from climate change. The dependency of farmed fish for these oils has a well-known physiological basis, which concerns an apparent deficiency in fish species to biosynthesise long chain polyunsaturated fatty acids (PUFA). Nevertheless it has been established that fish species contain the both the genes and the transcriptional machinery to make PUFA. I have hypothesised that a more rigorous understanding of the regulation of lipid biosynthetic genes in fish would allow the development of a framework for reducing or substituting oils derived from wild fish in the diets of farmed species. Ultimately this would allow the aquaculture industry to expand in a more environmentally sustainable manner than at present.
£183,016 from the BBSRC. ‘The role of peroxisome proliferator-activated receptors in regulating lipid metabolism in fish’. Dec 1999 to Dec 2002.
With Dr Douglas Tocher, Institute of Aquaculture, University of Stirling
€283,133 from the EC. ‘Cloning and functional analysis of fish peroxisome proliferator-activated receptors: The transcriptional control of lipid metabolism in farmed fish species’.
Dr Douglas Tocher, Institute of Aquaculture, University of Stirling
Dr Greg Krey, Fisheries Research Institute, Kavalla, Greece.
Dr Jose Bautista, University of Madrid Spain
2. Distribution of Tc1-like Mobile DNA Elements in Aquatic Animals
Transposons are mobile DNA elements which are widespread components of probably all genomes. I am interested in vertebrate elements related to the Tc1 family of C. elegans. To date no intact Tc1-like elements have been isolated from vertebrates; most copies exist as ‘fossilized’ components of genomes, that is they have accrued multiple mutations which render them non-mobilisable. However, I have recently isolated an apparently intact Tc1-like element from flatfish genomes and, furthermore, have shown that closely related elements are present in salmonid and frog genomes. The presence of these closely related elements in such diverse phyla and the fact that, at least in flatfish, they may be functional, raises the possibility of horizontal transmission. That is, they may have jumped between the genomes of different species. There is evidence from the DNA databases that very similar elements may exist in the genomes of schistosome parasites. I am interested in studying the possibility that related parasites of fish and frogs may be acting as vectors for the horizontal transmission of Tc1-like transposons and possibly for the transfer, more generally, of DNA between parasites and their hosts.
An active Tc1-like element from a vertebrate may also have a number of biotechnological uses. For example, in providing a universal system for transferring DNA between genomes, for developing high level protein expression systems, and for rapid genome mapping. I am currently testing these possibilities.
3. Molecular Adaptation to Environmental Change
I am interested in the possibility that particularly effective pollutant-metabolising genes may have been selected for in populations of fish living in long-term polluted environments. I have previously cloned and characterised a range of genes involved in pollutant metabolism from flatfish and I have established that these genes are highly variable within fish populations. (fish xenobiotic metabolism) It should be possible to develop population level molecular tests for pollutant-metabolising allele frequencies within populations from polluted and non-polluted environments. If differences exist, then it becomes feasible to test the functional significance of variation at particular pollutant-metabolising gene loci and also to test the fitness of individuals with particular gene variants. Such studies could provide direct measurements of the adaptive significance of genetic variation.
I am also interested in applying techniques emerging from the recently developed field of genomics to the issue of molecular adaptation and I am currently involved in a project to develop an EST library for Atlantic salmon. This will provide the basis for comparing global changes in gene expression and for isolating critical genes in fish subjected to different environmental influences.
€241,000 from the EC. ‘Generation of a Genetic Body Map for Atlantic Salmon.’
Dr. John Taggert and Dr. Margaret Cairney, Institute of Aquaculture, University
Dr Richie Powell, University of Galway, Eire
Dr Bjorn Hoyheim, College of Veterinary Medicine, Norway
Dr Christian Bendixen, Institute of Agricultural Sciences, Denmark