Division of Genetics and Genomics, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin Biocentre, Roslin, UK.
Anim Genet. 2010 Oct;41(5):531-6. doi: 10.1111/j.1365-2052.2010.02032.x.
In a previous study, three significant quantitative trait loci (QTL) associated with resistance to Infectious Pancreatic Necrosis (IPN) disease were identified by analysing challenge data from one sub-population of Landcatch Atlantic salmon (Salmo salar) smolt. While these QTL were shown to affect the resistance in seawater, their effect in freshwater was unknown. This study investigates the effect of these QTL on IPN resistance in salmon fry in freshwater. Twenty families with intermediate levels of IPN mortality were analysed from a freshwater challenge trial undertaken on a different sup-population of LNS salmon to that studied previously. Only the QTL from linkage group 21 (LG21) appeared to have a significant and large effect on resistance in freshwater; the same QTL was found to have the largest effect in seawater in the previous study. Variance component analysis showed a high heritability for the QTL: 0.45±0.07 on the liability scale and 0.25±0.05 on the observed scale. In a family where both parents were segregating for the QTL, there was a 0% vs. 100% mortality in homozygous offspring for resistant and susceptible QTL alleles. The finding that the same QTL has major effect in both freshwater and seawater has important practical implications, as this will allow the improvement of resistance in both phases through marker assisted selection by targeting this QTL. Moreover, the segregation of the LG21 QTL in a different sub-population gives further evidence of its association with IPN-resistance.
在之前的一项研究中，通过分析一个 Landcatch 大西洋鲑（Salmo salar）鱼苗群体的攻毒数据，鉴定出与传染性胰脏坏死（IPN）病抗性相关的三个显著数量性状位点（QTL）。虽然这些 QTL 被证明会影响海水养殖的抗性，但它们在淡水中的影响尚不清楚。本研究调查了这些 QTL 对淡水养殖鲑鱼苗 IPN 抗性的影响。在对来自先前研究的不同亚群体的 LNS 鲑鱼进行的淡水攻毒试验中，分析了 20 个具有中等 IPN 死亡率的家系。只有来自连锁群 21（LG21）的 QTL 似乎对淡水养殖的抗性有显著且较大的影响；在之前的研究中，该 QTL 被发现对海水养殖的影响最大。方差分量分析显示，该 QTL 的遗传力很高：在倾向得分尺度上为 0.45±0.07，在观测得分尺度上为 0.25±0.05。在家系中，如果父母双方都为 QTL 分离，那么在抗性和易感 QTL 等位基因的纯合后代中，死亡率分别为 0%和 100%。同一 QTL 在淡水和海水中均有主要影响的发现具有重要的实际意义，因为这将允许通过标记辅助选择靶向该 QTL 来提高两个阶段的抗性。此外，LG21 QTL 在不同亚群体中的分离为其与 IPN 抗性的关联提供了进一步的证据。
