Cardiomyopathy syndrome is a severe, viral disease of Atlantic salmon that mostly affects farmed animals during their late production stage at sea. Caused by piscine myocarditis virus (PMCV), over the past few years outbreaks due to this disease have resulted in significant losses to the aquaculture industry. However, there is currently no vaccine that has proven effective against this virus. In this study, using a challenge model, we investigated the genetic variation for resistance to PMCV, by screening a large number of animals using a 55 K SNP array. In particular, we aimed to identify genetic markers that are tightly linked to higher disease resistance and can potentially be used in breeding programs. Using genomic information, we estimated a heritability of 0.51 ± 0.06, suggesting that resistance against this virus, to a great extent, is controlled by genetic factors. Through association analysis, we identified a significant quantitative trait locus (QTL) on chromosome 27, explaining approximately 57% of the total additive genetic variation. The region harbouring this QTL contains various immune-related candidate genes, many of which have previously been shown to have a different expression profile between the naïve and infected animals. We also identified a suggestive association on chromosome 12, with the QTL linked markers located in two putatively immune-related genes. These results are of particular interest, as they can readily be implemented into breeding programs, can further assist in fine-mapping the causative mutations, and help in better understanding the biology of the disease and the immunological mechanisms underlying resistance against PMCV.

中文翻译：

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大西洋鲑鱼（Salmo salar）对鱼心肌炎病毒 (PMCV) 抗性的全基因组关联研究

心肌病综合征是大西洋鲑鱼的一种严重的病毒性疾病，主要影响在海上生产后期的养殖动物。由鱼心肌炎病毒 (PMCV) 引起，在过去几年中，由于这种疾病而爆发，给水产养殖业造成了重大损失。然而，目前还没有被证明对这种病毒有效的疫苗。在这项研究中，我们使用挑战模型，通过使用 55 K SNP 阵列筛选大量动物，研究了 PMCV 抗性的遗传变异。特别是，我们旨在确定与更高抗病性密切相关的遗传标记，并有可能用于育种计划。使用基因组信息，我们估计遗传率为 0.51 ± 0.06，这表明对该病毒的抗性在很大程度上，受遗传因素控制。通过关联分析，我们在 27 号染色体上确定了一个显着的数量性状基因座 (QTL)，解释了总加性遗传变异的大约 57%。包含该 QTL 的区域包含各种免疫相关候选基因，其中许多基因先前已被证明在未感染动物和受感染动物之间具有不同的表达谱。我们还在 12 号染色体上发现了一种暗示性关联，QTL 连锁标记位于两个假定的免疫相关基因中。这些结果特别令人感兴趣，因为它们可以很容易地实施到育种计划中，可以进一步帮助精细定位致病突变，并有助于更好地了解疾病的生物学和抵抗 PMCV 的免疫学机制。