-The completion of genomic sequences of physiologically important genes frequently reveals non-coding genetic elements such as tandem repeats (micro-and minisatellites) that are often more polymorphic than nearby coding sequences. We obtained the complete genomic sequences of three hormone genes in sea bass Dicentrarchus labrax: growth hormone (dlGH), somatolactin (dlSL) and insulin-like growth factor-1 (dlIGF-1), including 5 -and 3 -untranslated regions. Mini-and microsatellites were discovered in both flanking and intron regions. Some were partially conserved across Perciformes. To assess the usefulness and relevance of these gene-associated markers for understanding population structure, an investigation was made on genetic diversity and differentiation at four of them in (i) five wild populations from the North Sea, the Bay of Biscay and the Western Mediterranean, and (ii) two samples of hatchery-bred individuals from a freshwater-acclimation experiment. Gene and allelic diversities were lower in cultured individuals than in wild ones. Significant genetic differentiation was demonstrated between Bay of Biscay + North Sea and Mediterranean populations (F st > 0.06, p < 0.001), primarily due to dlGH-associated markers. Significant genetic differentiation was also detected among the Atlantic and North Sea samples, but restricted to the locus associated with dlSL. Significant genetic differentiation was also found among experimental individuals before and after a salinity challenge (F st ≈ 0.05, p < 0.001), but was due to dlSL and dlIGF-1 loci. Gene-associated markers proved to be more efficient than formerly used anonymous microsatellite markers in providing a clear picture of genetic differentiation.Key words: Growth hormone / Somatolactin / Insulin-like growth factor-1 / Non-coding regions / European sea bass / Microsatellites / Minisatellites Résumé -Connaître les séquences génomiques de gènes d'importance physiologique permet de déceler des élé-ments génétiques non-codants tels que des répétitions en tandem (micro -et minisatellites), souvent porteurs de davantage de polymorphismes que les séquences codantes voisines. Des séquences génomiques complètes ainsi que celles de leurs régions flanquantes en 5 et 3 sont établies pour trois gènes codants pour des hormones chez le bar, Dicentrarchus labrax : l'hormone de croissance (dlGH), la somatolactine (dlSL) et le facteur de croissance apparenté à l'insuline (dlIGF-1). Ainsi, un mini-et des microsatellites partiellement conservés chez les Perciformes ont été trouvés. Pour évaluer la pertinence de ces marqueurs pour des études de structure génétique des populations, leur diversité et leur différenciation génétiques sont examinées chez (i) cinq populations sauvages de la mer du Nord, du golfe de Gascogne et de la Méditerranée occidentale, ainsi que dans ( Resour. 23, 285-296 (2010) pour le locus associé à dlSL. Enfin, pour les marqueurs associés à dlSL et dlIGF-1, une différenciation génétique significative est mise en évidence entre individus expérim...