Cardiomyopathy syndrome is a viral disease of Atlantic salmon, mostly affecting fish during the late stages of production, resulting in significant losses to the industry. It has been shown that resistance to this disease has a strong genetic component, with quantitative trait loci (QTL) on chromosomes 27 (Ssa27) and Ssa12 to explain most of the additive genetic variance. Here, by analysing animals from a different year-class and a different population, we further aimed to confirm and narrow down the locations of these QTL. The data support the existence of the two QTL and suggest that the causative mutation on Ssa27 is most likely within the 10–10.5 Mbp segment of this chromosome. This region contains a cluster of major histocompatibility complex class I (MHC I) genes with the most strongly associated marker mapped to one of these loci. On Ssa12, the data confirmed the previous finding that the location of the causative mutation is within the 61.3 to 61.7 Mbp region. This segment contains several immune-related genes, but of particular interest are genes related to MHC II. Together, these findings highlight the likely key role of MHC genes in Atlantic salmon following infection with Piscine myocarditis virus (PMCV) and their potential impact on influencing the trajectory of this disease.

中文翻译：

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全基因组关联研究证实了先前在大西洋鲑鱼（Salmo salar L.）中影响对鱼心肌炎病毒抗性的主要位点的发现

心肌病综合征是大西洋鲑鱼的一种病毒性疾病，主要影响生产后期的鱼类，给该行业造成重大损失。已经表明，对这种疾病的抗性具有很强的遗传成分，27 号染色体 (Ssa27) 和 Ssa12 上的数量性状基因座 (QTL) 可以解释大部分的加性遗传变异。在这里，通过分析来自不同年级和不同种群的动物，我们进一步旨在确认和缩小这些 QTL 的位置。数据支持两个 QTL 的存在，并表明 Ssa27 上的致病突变最有可能在该染色体的 10-10.5 Mbp 片段内。该区域包含一组主要组织相容性复合体 I 类 (MHC I) 基因，其中关联性最强的标记映射到这些基因座之一。在 Ssa12，数据证实了之前的发现，即致病突变的位置在 61.3 至 61.7 Mbp 区域内。该片段包含几个免疫相关基因，但特别令人感兴趣的是与 MHC II 相关的基因。总之，这些发现突出了 MHC 基因在大西洋鲑鱼感染鱼心肌炎病毒 (PMCV) 后可能的关键作用及其对影响这种疾病发展轨迹的潜在影响。