Asian seabass is an important food fish species. While improving growth, increasing the nutritional value is important, omega-3 fatty acids are indispensable to human health. Identifying and validating DNA markers associated with traits is the first step towards marker-assisted selection (MAS). We quantified 13 different fatty acids and three growth traits in 213 F₂ Asian seabass from a family at the age 270 days post hatch, and screened QTL for these traits. The content of total fatty acids in 100 g flesh was 2.57 ± 0.80 g, while the proportions of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were 16.96 ± 2.20% and 5.42 ± 0.90%, respectively. A linkage map with 2424 SNPs was constructed and used for QTL mapping. For fatty acid compositions, 14 significant QTL were identified on three linkage groups (LG5, LG11 and LG14), with phenotypic variance explained (PVE) from 12.8 to 24.6%. Thirty-nine suggestive QTL were detected on 16 LGs. Two significant QTL for EPA were identified on LG5 and LG14, with PVE of 15.2% and 15.1%, respectively. No significant QTL was identified for DHA. For growth traits, six significant and 13 suggestive QTL were identified on two and seven LGs, respectively. Only a few significant QTL for fatty acids overlapped with previously mapped QTL for these traits, suggesting that most QTL detected in a family are family-specific and could only be used in MAS in the family per se. To facilitate population-wide molecular breeding, more powerful methods (e.g. GWAS) should be used to identify SNPs for genomic selection.

中文翻译：

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亚洲海鲈脂肪酸组成和生长性状的QTL定位和验证。

亚洲鲈鱼是重要的食用鱼类。在改善生长的同时，增加营养价值也很重要，但omega-3脂肪酸对人体健康必不可少。鉴定和验证与性状相关的DNA标记是迈向标记辅助选择（MAS）的第一步。我们对213 F _2中的13种不同脂肪酸和3种生长性状进行了定量孵化后270天的一个家庭的亚洲鲈鱼，并筛选了QTL的这些特征。100克肉中总脂肪酸含量为2.57±0.80 g，二十二碳六烯酸（DHA）和二十碳五烯酸（EPA）的比例分别为16.96±2.20％和5.42±0.90％。构建了具有2424个SNP的连锁图，并将其用于QTL定位。对于脂肪酸组成，在三个连接基团（LG5，LG11和LG14）上鉴定出14个重要的QTL，表型变异解释为（PVE）从12.8至24.6％。在16个LG上检测到39个提示性QTL。在LG5和LG14上鉴定出两个重要的EPA QTL，PVE分别为15.2％和15.1％。没有发现DHA的重要QTL。对于生长性状，分别在两个和七个LG上鉴定了六个重要和13个暗示性QTL。仅有几个重要的脂肪酸QTL与这些特性的先前映射QTL重叠，这表明在一个家庭中检测到的大多数QTL是特定于家庭的，只能在该家庭本身的MAS中使用。为了促进整个人群的分子育种，应使用更强大的方法（例如GWAS）来鉴定用于基因组选择的SNP。