PARENTAGE ASSIGNMENT USING MICROSATELLITES IN TURBOT (SCOPHTHALMUS-MAXIMUS) AND RAINBOW-TROUT (ONCORHYNCHUS-MYKISS) HATCHERY POPULATIONS

Eight turbot (Scophthalmus maximus) and eight rainbow trout (Oncorhync hus mykiss) microsatellites were selected for parentage assignment in fish-farmed populations. The number of alleles, gene diversity, polymo rphic information content, and the probabilities of exclusion of these loci were 8, 0.76, 0.73, and 0.55 in turbot and 4, 0.65, 0.59 and 0.3 9 in rainbow trout, respectively. The power of the markers for parenta ge assignment was assessed by computing the frequency of good and uniq ue decisions (f(gu)) in a population of genitors defined by its allele frequencies and assuming three different types of mating schemes. The eight turbot microsatellites gave larger maximal mating schemes (the largest mating structure with a f(gu) greater than or equal to 0.95) t han the eight rainbow trout loci: 1 female (F) mated to 520 males (M) (paternity retrieval scheme), more than 140F x 140M (factorial scheme) , and more than 15000 independent pairs (natural population scheme) fo r turbot, and 1F x 88M, 34F x 34M, and 7000 independent pairs for rain bow trout. The variation of the f(gu) values with the number of loci c onfirmed that the turbot set of microsatellites was more efficient for parentage assignment than the rainbow trout markers.