Obiettivo The main aim of this project is to develop and evaluate new techniques for identifying genetic variation in commercially important marine species. An assessment will be made of the value of these techniques in fisheries management with particular reference to stock identification in the whiting, Gadus merlangus, a species of major commercial interest. The project is concerned with the stock identification of populations in Merlangius melangus (whiting) to achieve this 2 novel techniques are being developed and compared against 2 established techniques. The former will be an analysis of Mini-Microsatellite sequences in nuclear deoxyribonucleic acid (DNA) and the latter are an analysis of mitochondrial DNA and an electrophoretic study of protein variation. Minisatellite Nuclear DNA analysis relies upon variation between individuals in the length of fragments of DNA made up of repeats flanked by unique sequences. Following restriction, enzyme digestion of the nuclear DNA and gel electrophoresis, the fragments can be identified by single locus probes which recognise the unique flanking sequences. Within each locus, several alleles segregate in most animal species that have been investigated so far. It has already been shown with salmonid fishes that such probes identify considerable genetic variation. Microsatellites are shorter lengths of DNA consisting of a number of repeats of pairs of bases, again flanked by unique sequences. The number of these tandem repeats is variable between individuals. Microsatellite loci can be an important source of polymorphic genetic markers for population genetics studies. In results to date allozyme variation at 7 polymorphic enzyme loci has been examined by gel electrophoresis. Samples from the Irish Sea, the North Sea, the Baltic Sea and the Norwegian coast have been analyzed with no differences being found between areas. 2 minisatellite loci have been identified, both with high levels of variability. Comparisons between samples from different areas are being made. 13 microsatellite loci have been found so far and are being tested for variability and differences between samples from different areas.Until recently the most common method used in the genetic identification of populations has been protein electrophoresis. When applied to the management of commercially important marine species this technique has been of limited value as little evidence of fish stock structure has been observed. However, it is recognised that protein electrophoresis detects only 30% of base changes in the genetic material (deoxyribonucleic acid (DNA)). Furthermore the class of genes whose products are detected by protein electrophoresis are thought to evolve slowly and may therefore not be appropriate for identifying relatively recent genetic divergence. Recent developments in molecular genetics have enabled direct studies to be made on DNA itself. Higher levels of genetic variation have been found giving far greater degrees of resolution in population identification. The techniques available can variously discriminate between individuals, families, populations, races, subspecies and species. This project will be concerned with the identification of populations in the whiting, Gadus melangus, and, to achieve this, 2 novel techniques will be developed and compared against 2 established techniques. The former will be an analysis of minisatellite nuclear DNA and a study of amplified polymorphic DNA sequences (APS); the latter will be a restriction fragment length polymorphism (RFLP) analysis of mitochondrial DNA (mtDNA) and an electrophoretic study of protein variation. Minisatellite nuclear DNA analysis is a relatively new molecular method. It relies upon variation between individuals in the length of fragments of DNA made up of repeats flanked by unique sequences. Following restriction enzyme digestion of the nuclear DNA and gel electrophoresis, the fragments can be identified by single locus probes which recognise the unique flanking sequences. Within each locus, several alleles segregate in most animal species that have been investigated so far. It has already been shown with salmonid fishes that such probes identify considerable genetic variation. APS are sequences in the genome where regions are known to be polymorphic, such as ribosomal DNA (rDNA) and mtDNA, for which the flanking regions are highly conserved and for which primers are already available. Using pairs of these primers the sequences between them can be amplified by the polymerase chain reaction (PCR) technique, the DNA base sequence determined and the detailed genetic divergence between the samples measured. It can identify single base differences and gives a complete sequence between primers. Campo scientifico natural sciencesbiological sciencesmolecular biologymolecular geneticsnatural sciencesbiological sciencesgeneticsDNAnatural scienceschemical scienceselectrochemistryelectrophoresisnatural sciencesbiological sciencesgeneticsgenomesnatural sciencesbiological sciencesbiochemistrybiomoleculesproteinsenzymes Programma(i) FP2-FAR - Community research and coordination programmes (EEC) in the fisheries sector, 1988-1992 Argomento(i) Data not available Invito a presentare proposte Data not available Meccanismo di finanziamento Data not available Coordinatore THE MINISTER OF AGRICULTURE, FISHERIES AND FOOD Contributo UE Nessun dato Indirizzo Smith Square 17, Nobel House SW1P 3JR LONDON Regno Unito Mostra sulla mappa Costo totale Nessun dato Partecipanti (2) Classifica in ordine alfabetico Classifica per Contributo UE Espandi tutto Riduci tutto UNIVERSITY COLLEGE CORK-DEPT OF ZOOLOGY Irlanda Contributo UE Nessun dato Indirizzo Cork Mostra sulla mappa Costo totale Nessun dato University of East Anglia Regno Unito Contributo UE Nessun dato Indirizzo University Plain NR4 7TJ Norwich Mostra sulla mappa Collegamenti Sito web Opens in new window Costo totale Nessun dato
