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：大西洋鲑鱼水产养殖业正探索利用无菌三倍体（triploid）以减轻其与野生同种个体的基因交流的可行性。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结论。已有研究在三倍体与二倍体鲑科鱼类中鉴定出基因表达的剂量效应与剂量补偿效应，但尚无研究探讨在大西洋鲑鱼的不同选育品系（即生长缓慢的野生型与生长快速的驯化型表型）中，倍性（ploidy）与亲本来源效应如何共同作用于多基因性状。本研究开展两项实验，探究二倍体与三倍体的纯野生（驯化基因组占比0%）、纯驯化（驯化基因组占比100%）以及F1互交杂种（驯化基因组占比33%、50%或66%）大西洋鲑的淡水生长性能；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，互交杂种的生长受第二条母源染色体的剂量效应影响：当母本为驯化个体时（驯化基因组占比从50%提升至66%），个体生长随倍性水平升高而提升；而当母本为野生个体时则呈现相反趋势（驯化基因组占比从50%降至33%）。
研究结论：本研究证实，作为多基因性状的生长，其受倍性与亲本来源的联合效应遵循加性调控模式。因此，若要最大化养殖生长潜力，水产养殖业在商业化生产三倍体家系时，应更注重母本的育种价值而非父本。