Genetic structure of domestic and natural populations of the Nile tilapia, Oreochromis niloticus in Burkina Faso, West Africa

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Abstracts / Aquaculture 272S1 (2007) S238–S321

friendly means of assessing health and performance. The project is a partnership involving three UK universities (Aberdeen, Cardiff and Stirling) and the Norwegian Salmon Genome Project (NSGP), supported by ARK-Genomics and working in collaboration with Operon and Marine Harvest (a division of Nutreco). It is linked to the salmon farming industry through Scottish Quality Salmon, an organisation representing a majority of producers in the UK. The goal of TRAITS is to develop an oligonucleotide array for probing key elements of the transcriptome involved in polyunsaturated fatty acid metabolism, protein catabolism, responses to bacterial and viral challenge, and the process of freshwater to seawater adaptation (smoltification). We report here on a preliminary deliverable of this project, a 17K gene Atlantic salmon cDNA microarray. Details of its construction and preliminary verification are presented. The microarray, and associated resources, are available through ARK-Genomics (http://www.ark-genomics.org). doi:10.1016/j.aquaculture.2007.07.192

reducing incidence of deformities and improving external pigmentation are additional traits included as breeding goals. The family based design allows for inclusion of any recordable trait of economic importance as the programs develop and new traits under consideration for inclusion are improved disease resistance and carcass quality. The high fecundity rate of the species gives a significant risk for inbreeding and depression. Control of pedigree and the wide background in the base population in the programs allows us to handle this challenge. In the sea bream program the first offspring after selected males (produced in 2004) are performance tested and the nucleus families of the F1 generation will be produced during the first months of 2006. Regarding sea bass, selection of males from the base population to produce new families will be done during spring 2006. Estimates of genetic parameters for production traits and predicted selection responses based on selection differentials will be presented, as well as comparisons of the performance of the family selected versus alternative genetic material in commercial production in Greece. doi:10.1016/j.aquaculture.2007.07.193

Family based selection for production traits in gilthead seabream (Sparus aurata) and European sea bass (Dicentrarchus labrax) in Greece I. Thorland a, N. Papaioannou b, L. Kottaras b, T. Refstie a, S. Papasolomontos b, M. Rye a a Akvaforsk Genetics Center AS N-6600 Sunndalsøra, Norway b KEGO S.A. 1st km Artaki Psahna Rd., 346 00 N. Artaki, Greece The implementation of systematic genetic improvement programs is essential for the development of cost effective and sustainable aquaculture productions. Programs for species such as Atlantic salmon and tilapia have demonstrated the effectiveness of the application of quantitative methods to fish. Somewhat surprisingly, the bass and bream industry in the Mediterranean region of Europe has until recently been slow to take up this technology and thus failed to obtain highly significant improvements in production efficiency as seen for other key aquaculture species. On this background KEGO S.A., a leading provider of genetically improved livestock in Greece, initiated large scale, family based selection programs for sea bream (Sparus aurata) and sea bass (Dicentrarchus labrax) in 2002 and 2004, respectively. The programs are initially focused primarily on improving growth rate, but

Genetic structure of domestic and natural populations of the Nile tilapia, Oreochromis niloticus in Burkina Faso, West Africa A. Toguyeni a, S. Thévenon b, E. Soara b, H. D'Cotta c, J.F. Baroiller c , X. Rognon d a Institut des Sciences de la Nature et de la Vie, Université Polytechnique de Bobo-Dioulasso, 01 BP 1091, Bobo-Dioulasso 01, Burkina Faso, West Africa b Centre International de Recherche-Développement sur l'Elevage en Zone subhumide, 01 BP. 454 BoboDioulasso 01-Burkina Faso, West Africa c UPR20 Aquaculture et gestion des ressources aquatiques, CIRAD-EMVT, Campus International de Baillarguet, TA 30/A, 34398 Montpellier cedex 5, France d UMR Génétique et Diversité Animales, INA-PG, 16, rue Claude Bernard, 75231 Paris cedex 05, France The present study is part of an aquaculture developmental program held in Burkina Faso. The final aim is to generate a genetic selection program for an Oreochromis niloticus strain presenting good performances in both growth and reproduction. A characterization of the genetic diversity within and between wild and domestic populations was performed using Restricted Fragment Length Polymorphism (RFLP) of the mitochondrial

Abstracts / Aquaculture 272S1 (2007) S238–S321

DNA (mtDNA). Muscle or fins were sampled from 142 individuals in 7 different sites on the 3 main hydrographic basins of Burkina Faso (Comoé, Volta and Niger). DNA was extracted using a commercial kit (Promega). The fragment Nd-5/6 (2 500 bp) of mtDNA was amplified by PCR using primers C-GLU and CLEU3. The amplified products were then digested using one of the six following restriction enzymes: AluI, HaeIII, HinfI, HpaII, RsaI, and Taq I. Haplotype frequencies of the mtDNA per population were calculated from the mtDNA data. When using TaqI, we obtained 4 haplotypes in the basin of Comoé, 3 in that of Volta and only one in the basin of Niger. While the haplotype B is fixed in the Niger basin and the haplotype C dominants in the Comoé basin, haplotype A is only found in the Volta basin. Within the Volta basin, we observed differences in the C haplotype frequencies when we compared the domesticated Bazèga population with the wild population of Bama. The populations of Bazèga could have been introgressed by those coming from Kompienga as the frequency of haplotype C is higher in the Kompienga population, also visible in the Bazèga population. It appears that some individuals of Kompienga population are also maintained in the same rearing station of Bazèga. This distribution revealed heterogeneity of the Oreochromis niloticus populations of Burkina Faso. A larger number of individuals are being analysed presently with Taq I in order to validate these results. Further studies will consider the possible association of these genetic population differences, with growth and reproduction performances. doi:10.1016/j.aquaculture.2007.07.194

Quantitative genetic determinism of sex-ratio in the European sea bass (Dicentrarchus labrax L.) M. Vandeputte a,b, M. Dupont-Nivet b, O. Merdy b, P. Haffray c, H. Chavanne d, B. Chatain a a,b INRA UR544 Génétique des Poissons, F-78350 Jouy en Josas, France b IFREMER, Chemin de Maguelone, F-34250 Palavas les Flots, France c Sysaaf, Station SCRIBE, F-35000 Rennes, France d Panittica Pugliese, I-72010 Torre Canne di FasanoBR, Italy Farmed populations of seabass usually comprise around 80% of males, which is a drawback for the producers, as males are 20–30% smaller than females and mature earlier. The sex determinism system in this

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species has been shown to be unusual, with a lack of sex chromosomes and an important environmental sex determinism. In this experiment, we tested the hypothesis that sex determinism in seabass could be under a polygenic control. We produced 253 full-sib families from 33 males and 23 females in a partial factorial mating design. At 1 year of age, 7500 individuals were PIT-tagged. 5960 of those were sexed at 2 years of age, 5893 (98.9%) of which could be assigned to a single parental pair with 6 microsatellites. The mean proportion of females in the population was 18%. Full-sib family sex ratio was largely influenced by male and female parents: the proportion of females by sire halfsibs family varies between 5 and 46%, and the variation between dam half-sibs families is similar. The heritability of sex ratio on the underlying liability scale was estimated to be 0.52 ± 0.13. There was a positive genetic correlation (0.50 ± 0.09) between sex ratio and growth. The implications of these findings for the evolution of sex ratio in cultured seabass populations will be discussed. doi:10.1016/j.aquaculture.2007.07.195

Microsatellte evolution in rainbow trout and Atlantic salmon from Chile R. Vidal Laboratory of Molecular Ecology and Evolutionary Studies, Departament of Biology, Faculty of Biology, University of Santiago, Chile Laboratory Diagnotec S.A, Santiago, Chile Microsatellites are arguably the most important class of genetic markers yet discovered, comprising arrays of short highly variable tandemly repeated motifs often useful for genome mapping, parentage verification and diversity analysis. Several studies suggest that the median allele length of microsatellites is longest in the species from which the markers were derived, suggesting that an ascertainment bias was operating. This fact is very important because the allele length is a major factor influencing mutation rate. We have examined whether the size distribution of microsatellite alleles between trout and Atlantic salmon is source dependent using a set of 10 microsatellites that can be amplified in both species. For those markers that were polymorphic in both species we report a significantly greater number of markers (P b 0.001) with longer median allele sizes in Atlantic salmon, regardless of microsatellite origin. This finding suggests that any ascertainment bias operating