Data from: Stocking impacts the expression of candidate genes and physiological condition in introgressed brook charr (Salvelinus fontinalis) populations

Translocation of plants and animal populations between environments is one of the major forms of anthropogenic perturbation experienced by pristine populations, and consequently, human mediated hybridization by stocking practices between wild and exogenous conspecifics is of increasing concern. In this study, we compared the expression of seven candidate genes involved in multifactorial traits and regulatory pathways for growth as a function of level of introgressive hybridization between wild and domestic brook charr to test the null hypothesis of no effect of introgression on wild fish. Our analyses revealed that the expression of two of the genes tested, cytochrome c oxidase VIIa and the growth hormone receptor isoform I, was positively correlated with the level of introgression. We also observed a positive relationship between the extent of introgression and physiological status quantified by the Fulton’s condition index. The expression of other genes was influenced by other variables, including year of sampling (reflecting different thermal conditions), sampling method and lake of origin. This is the first demonstration in nature that introgression from stocked populations has an impact on the expression of genes playing a role in important biological functions that may be related with fitness in wild introgressed populations.

跨生境动植物种群的易地移殖，是原生种群所面临的主要人为干扰形式之一；由此引发的野外种群与外来同物种种群间通过增殖放流活动形成的人为介导杂交，正日益受到学界关注。本研究以野生与养殖溪红点鲑的渐渗杂交（introgressive hybridization）水平为变量，比较了7个与多因子性状及生长调控通路相关的候选基因的表达量，以检验“渐渗作用对野生鱼类无影响”的原假设。分析结果显示，所检测的7个基因中，细胞色素C氧化酶VIIa（cytochrome c oxidase VIIa）与生长激素受体亚型I（growth hormone receptor isoform I）的表达量与渐渗杂交水平呈正相关；此外，渐渗程度与通过富尔顿状况指数（Fulton’s condition index）量化的生理状态之间同样存在正相关关系。其余基因的表达量则受采样年份（反映不同水温条件）、采样方法以及起源湖泊等其他变量影响。本研究首次在自然环境中证实：增殖放流种群的渐渗作用，会对野生渐渗种群中与适合度相关的重要生物学功能基因的表达产生影响。