Molecular Population Genetics Group, Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, 117604 Singapore, Singapore.
BMC Genomics. 2013 May 1;14:295. doi: 10.1186/1471-2164-14-295.
Aquaculture is the quickest growing sector in agriculture. However, QTL for important traits have been only identified in a few aquaculture species. We conducted QTL mapping for growth traits in an Asian seabass F(2) family with 359 individuals using 123 microsatellites and 22 SNPs, and performed association mapping in four populations with 881 individuals.
Twelve and nine significant QTL, as well as 14 and 10 suggestive QTL were detected for growth traits at six and nine months post hatch, respectively. These QTL explained 0.9-12.0% of the phenotypic variance. For body weight, two QTL intervals at two stages were overlapped while the others were mapped onto different positions. The IFABP-a gene located in a significant QTL interval for growth on LG5 was cloned and characterized. A SNP in exon 3 of the gene was significantly associated with growth traits in different populations.
The results of QTL mapping for growth traits suggest that growth at different stages was controlled by some common QTL and some different QTL. Positional candidate genes and association mapping suggest that the IFABP-a is a strong candidate gene for growth. Our data supply a basis for fine mapping QTL, marker-assisted selection and further detailed analysis of the functions of the IFABP-a gene in fish growth.
水产养殖是农业中发展最快的领域。然而，重要性状的 QTL 仅在少数几种水产养殖物种中被鉴定出来。我们使用 123 个微卫星和 22 个 SNP，对一个 359 个个体的亚洲海鲈 F2 家系进行了生长性状的 QTL 作图，并对四个 881 个个体的群体进行了关联作图。
在孵化后 6 个月和 9 个月时，分别检测到了 12 个和 9 个显著 QTL，以及 14 个和 10 个暗示 QTL，用于生长性状。这些 QTL 解释了 0.9-12.0%的表型方差。对于体重，两个阶段的两个 QTL 区间重叠，而其他的则映射到不同的位置。IFABP-a 基因位于 LG5 上一个生长显著 QTL 区间内，并被克隆和特征化。该基因外显子 3 中的一个 SNP 与不同群体的生长性状显著相关。
生长性状的 QTL 作图结果表明，不同阶段的生长由一些共同的 QTL 和一些不同的 QTL 控制。候选基因的定位和关联作图表明，IFABP-a 是生长的一个强候选基因。我们的数据为 QTL 的精细作图、标记辅助选择以及进一步详细分析 IFABP-a 基因在鱼类生长中的功能提供了基础。
