ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia.
School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW, 2007, Australia.
Glob Chang Biol. 2017 Jan;23(1):307-317. doi: 10.1111/gcb.13419. Epub 2016 Jul 29.
Predicting the impacts of climate change requires knowledge of the potential to adapt to rising temperatures, which is unknown for most species. Adaptive potential may be especially important in tropical species that have narrow thermal ranges and live close to their thermal optimum. We used the animal model to estimate heritability, genotype by environment interactions and nongenetic maternal components of phenotypic variation in fitness-related traits in the coral reef damselfish, Acanthochromis polyacanthus. Offspring of wild-caught breeding pairs were reared for two generations at current-day and two elevated temperature treatments (+1.5 and +3.0 °C) consistent with climate change projections. Length, weight, body condition and metabolic traits (resting and maximum metabolic rate and net aerobic scope) were measured at four stages of juvenile development. Additive genetic variation was low for length and weight at 0 and 15 days posthatching (dph), but increased significantly at 30 dph. By contrast, nongenetic maternal effects on length, weight and body condition were high at 0 and 15 dph and became weaker at 30 dph. Metabolic traits, including net aerobic scope, exhibited high heritability at 90 dph. Furthermore, significant genotype x environment interactions indicated potential for adaptation of maximum metabolic rate and net aerobic scope at higher temperatures. Net aerobic scope was negatively correlated with weight, indicating that any adaptation of metabolic traits at higher temperatures could be accompanied by a reduction in body size. Finally, estimated breeding values for metabolic traits in F2 offspring were significantly affected by the parental rearing environment. Breeding values at higher temperatures were highest for transgenerationally acclimated fish, suggesting a possible role for epigenetic mechanisms in adaptive responses of metabolic traits. These results indicate a high potential for adaptation of aerobic scope to higher temperatures, which could enable reef fish populations to maintain their performance as ocean temperatures rise.
预测气候变化的影响需要了解适应气温上升的潜力，而大多数物种的这种潜力是未知的。适应潜力在热带物种中可能尤为重要，因为它们的温度范围较窄，并且生活在接近最佳温度的环境中。我们使用动物模型来估计适应相关特征表型变异性的遗传力、基因型与环境互作和非遗传母体成分，该模型以珊瑚礁雀鲷（Acanthochromis polyacanthus）为研究对象。从野外捕获的繁殖对的后代在当前温度和两个升高温度处理（+1.5 和+3.0°C）下被饲养了两代，这与气候变化预测一致。在四个幼体发育阶段测量了长度、体重、身体状况和代谢特征（静止和最大代谢率以及净需氧量范围）。在孵化后 0 天和 15 天（dph），长度和体重的加性遗传变异较低，但在 30 dph 时显著增加。相比之下，长度、体重和身体状况的非遗传母体效应在 0 天和 15 dph 时较高，而在 30 dph 时较弱。代谢特征，包括净需氧量范围，在 90 dph 时具有较高的遗传力。此外，基因型与环境的显著互作表明，在更高温度下最大代谢率和净需氧量范围具有潜在的适应能力。净需氧量范围与体重呈负相关，表明在更高温度下代谢特征的任何适应都可能伴随着体型的减小。最后，F2 后代代谢特征的估计育种值受到亲本饲养环境的显著影响。在跨代驯化鱼中，代谢特征的育种值在较高温度下最高，这表明表观遗传机制可能在代谢特征的适应反应中发挥作用。这些结果表明，有氧范围对更高温度的适应潜力很高，这可能使珊瑚礁鱼类种群能够在海洋温度上升时保持其表现。
