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Abstract：
Domestication leads to changes in traits that are under directional selection in breeding programmes, though unintentional changes in nonproduction traits can also arise. In offspring of escaping fish and any hybrid progeny, such unintentionally altered traits may reduce fitness in the wild. Atlantic salmon breeding programmes were established in the early 1970s, resulting in genetic changes in multiple traits. However, the impact of domestication on eye size has not been studied. We measured body size corrected eye size in 4000 salmon from six common garden experiments conducted under artificial and natural conditions, in freshwater and saltwater environments, in two countries. Within these common gardens, offspring of domesticated and wild parents were crossed to produce 11 strains, with varying genetic backgrounds (wild, domesticated, F1 hybrids, F2 hybrids and backcrosses). Size-adjusted eye size was influenced by both genetic and environmental factors. Domesticated fish reared under artificial conditions had smaller adjusted eye size when compared to wild fish reared under identical conditions, in both the freshwater and marine environments, and in both Irish and Norwegian experiments. However, in parr that had been introduced into a river environment shortly after hatching and sampled at the end of their first summer, differences in adjusted eye size observed among genetic groups were of a reduced magnitude and were nonsignificant in 2-year-old sea migrating smolts sampled in the river immediately prior to sea entry. Collectively, our findings could suggest that where natural selection is present, individuals with reduced eye size are maladapted and consequently have reduced fitness, building on our understanding of the mechanisms that underlie a well-documented reduction in the fitness of the progeny of domesticated salmon, including hybrid progeny, in the wild.
摘要：
驯化导致在育种计划中处于定向选择下的性状发生变化，尽管非生产性状的无意变化也可能出现。在逃逸鱼的后代和任何杂种后代中，这种无意中改变的特征可能会降低野外的适应性。大西洋鲑鱼育种计划于1970年代初建立，导致多个性状的遗传变化。然而,驯化对眼睛大小的影响尚未研究。我们从人工和自然条件下进行的六个常见花园实验中测量了4000条鲑鱼的体型校正眼睛大小，在淡水和盐水环境中，在两个国家。在这些普通的花园中，驯化和野生亲本的后代杂交产生11个菌株，具有不同的遗传背景(野生，驯化,F1杂种，F2杂种和回交）。大小调整的眼睛大小受遗传和环境因素的影响。与在相同条件下饲养的野生鱼相比，在人工条件下饲养的驯养鱼的调整后的眼睛尺寸较小，在淡水和海洋环境中，在爱尔兰和挪威的实验中。然而,在帕尔，孵化后不久被引入河流环境，并在第一个夏天结束时取样，遗传组之间观察到的调整后眼睛大小的差异降低了幅度，并且在入海前立即在河中采样的2岁海移性smol中没有显着。总的来说，我们的发现可能表明，在自然选择存在的地方，眼睛大小减小的个体适应不良，因此健身能力下降，基于我们对有充分记录的驯化鲑鱼后代适应性降低的机制的理解，包括杂种后代，在野外。
