Data from: Ploidy elicits a whole-genome dosage effect: growth of triploid Atlantic salmon is linked to the genetic origin of the second maternal chromosome set

Background: The Atlantic salmon aquaculture industry is investigating the feasibility of using sterile triploids to mitigate genetic interactions with wild conspecifics, however, studies investigating diploid and triploid performance often show contrasting results. Studies have identified dosage and dosage-compensation effects for gene expression between triploid and diploid salmonids, but no study has investigated how ploidy and parent-origin effects interact on a polygenic trait in divergent lines of Atlantic salmon (i.e. slow growing wild versus fast growing domesticated phenotype). This study utilised two experiments relating to the freshwater growth of diploid and triploid groups of pure wild (0% domesticated genome), pure domesticated (100% domesticated genome), and F1 reciprocal hybrid (33%, 50% or 66% domesticated genome) salmon where triploidy was either artificially induced (experiment 1) or naturally developed/spontaneous (experiment 2). Results: In both experiments, reciprocal hybrid growth was influenced by the dosage effect of the second maternal chromosome, with growth increasing as ploidy level increased in individuals with a domesticated dam (from 50% to 66% domesticated genome), and the inverse in individuals with a wild dam (from 50% to 33% domesticated genome). Conclusions: We demonstrate that the combined effect of ploidy and parent-origin on growth, a polygenic trait, is regulated in an additive pattern. Therefore, in order to maximise growth potential, the aquaculture industry should consider placing more emphasis on the breeding value of the dam than the sire when producing triploid families for commercial production.研究背景：大西洋鲑鱼养殖业正探索使用无菌三倍体（triploid）以缓解其与野生同种个体产生的遗传互作的可行性。然而，针对二倍体（diploid）与三倍体养殖性能的相关研究往往得出相悖的结论。已有研究证实了鲑科鱼类（salmonids）中三倍体与二倍体间基因表达的剂量效应与剂量补偿效应，但目前尚无研究探讨倍性（ploidy）与亲本来源效应的交互作用，如何影响大西洋鲑鱼不同选育品系的多基因性状（polygenic trait）——即生长缓慢的野生表型与生长快速的驯化表型之间的差异。本研究开展两项实验，聚焦二倍体与三倍体群体的淡水生长性能，受试群体包括纯野生（驯化基因组占比0%）、纯驯化（驯化基因组占比100%）以及F1正反交杂种（reciprocal hybrid，驯化基因组占比33%、50%或66%）大西洋鲑鱼；其中三倍体分别通过人工诱导（实验1）与自然发生/自发形成（实验2）两种方式获得。研究结果：两项实验均显示，正反交杂种的生长性能受第二条母源染色体的剂量效应调控：当母本（dam）为驯化品系时，个体的生长速率随倍性升高而提升（驯化基因组占比从50%升至66%）；而当母本为野生品系时，结果则恰好相反（驯化基因组占比从50%降至33%）。研究结论：本研究证实，倍性与亲本来源对生长这一多基因性状的联合调控遵循加性模式。因此，若要最大化养殖群体的生长潜力，大西洋鲑鱼养殖业在商业生产中培育三倍体家系时，应更重视母本的育种价值而非父本（sire）。