Palaiokostas Christos, Bekaert Michaël, Taggart John B, Gharbi Karim, McAndrew Brendan J, Chatain Béatrice, Penman David J, Vandeputte Marc
Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA, Scotland, UK.
The Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK.
Genet Sel Evol. 2015 Sep 4;47(1):68. doi: 10.1186/s12711-015-0148-y.
European sea bass (Dicentrarchus labrax) is one of the most important farmed species in Mediterranean aquaculture. The observed sexual growth and maturity dimorphism in favour of females adds value towards deciphering the sex determination system of this species. Current knowledge indicates the existence of a polygenic sex determining determination system that interacts with temperature. This was explored by restriction-site associated DNA (RAD) marker analysis in a test panel of 175 offspring that originated from a factorial cross between two dams and four sires from a single full-sib family.
The first high-density single nucleotide polymorphism (SNP) based linkage map for sea bass was constructed, consisting of 6706 SNPs on 24 linkage groups. Indications for putative sex-determining QTL (quantitative trait loci) that were significant at the genome-wide threshold were detected on linkage groups 6, 11 and 18 to 21, although a genome-wide association study (GWAS) did not identify individual significant SNPs at a genome-wide threshold. A preliminary genomic prediction approach that tested the efficiency of SNP-based selection for female sea bass showed a slight advantage compared to traditional pedigree-based selection. However, when the same models were tested on the same animals for selection for greater length, a clear advantage of the SNP-based selection was observed.
Overall, the results of this study provide additional support to the polygenic sex determination hypothesis in sea bass. In addition, identification of sex-ratio QTL may provide new opportunities for sex-ratio control in sea bass.
欧洲海鲈（Dicentrarchus labrax）是地中海水产养殖中最重要的养殖品种之一。观察到的有利于雌性的性生长和成熟二态性增加了破译该物种性别决定系统的价值。目前的知识表明存在一种与温度相互作用的多基因性别决定系统。通过对来自单个全同胞家系的两只母本和四只父本之间的析因杂交产生的175个后代的测试组进行限制性位点相关DNA（RAD）标记分析，对这一系统进行了探索。
构建了首个基于高密度单核苷酸多态性（SNP）的海鲈连锁图谱，该图谱由24个连锁群上的6706个SNP组成。在连锁群6、11和18至21上检测到了在全基因组阈值下显著的假定性别决定QTL（数量性状基因座）迹象，尽管全基因组关联研究（GWAS）在全基因组阈值下未识别出单个显著的SNP。一种测试基于SNP的雌性海鲈选择效率的初步基因组预测方法与传统的基于系谱的选择相比显示出轻微优势。然而，当在相同动物上测试相同模型以选择更长的体长时，基于SNP的选择显示出明显优势。
总体而言，本研究结果为海鲈的多基因性别决定假说提供了额外支持。此外识别性别比例QTL可能为海鲈的性别比例控制提供新机会。
