Data from: Geographic variation in phenotypic plasticity in response to dissolved oxygen in an African cichlid fish

Genetic adaptation and phenotypic plasticity are two ways in which organisms can adapt to local environmental conditions. We examined genetic and plastic variation in gill and brain size among swamp (low oxygen; hypoxic) and river (normal oxygen; normoxic) populations of an African cichlid fish, Pseudocrenilabrus multicolor victoriae. Larger gills and smaller brains should be advantageous when oxygen is low, and we hypothesized that the relative contribution of local genetic adaptation versus phenotypic plasticity should be related to potential for dispersal between environments (due to gene flow's constraint on local genetic adaptation). We conducted a laboratory-rearing experiment, with broods from multiple populations raised under high- and low-oxygen conditions. We found that most of the variation in gill size was due to plasticity. However, both plastic and genetic effects on brain mass were detected, as were genetic effects on brain mass plasticity. F1 offspring from populations with the highest potential for dispersal between environments had characteristically smaller and more plastic brains. This phenotypic pattern might be adaptive in the face of gene flow, if smaller brains and increased plasticity confer higher average fitness across environment types.遗传适应（genetic adaptation）与表型可塑性（phenotypic plasticity）是生物适应局域环境条件的两种核心途径。本研究以非洲慈鲷维多利亚朴丽鱼（Pseudocrenilabrus multicolor victoriae）的沼泽（低氧/缺氧（hypoxic））种群与河流（正常氧/常氧（normoxic））种群为研究对象，检测了其鳃部与脑部尺寸的遗传变异及表型可塑性变异。低氧环境下，更大的鳃部尺寸与更小的脑部尺寸应具备适应性优势；本研究提出假说：局域遗传适应与表型可塑性的相对贡献程度，应与种群在不同环境间的扩散潜力相关，这是由于基因流会对局域遗传适应产生约束作用。我们开展了室内饲养实验，将多个种群的子代幼体分别置于高氧与低氧环境下饲养。研究结果显示，鳃部尺寸的绝大多数变异均由表型可塑性导致。然而，本研究同时检测到表型可塑性与遗传效应对脑部质量存在影响，且遗传效应对脑部质量的表型可塑性亦存在作用。环境扩散潜力最高的种群所产生的F1子代，其脑部尺寸普遍更小且表型可塑性更强。若更小的脑部尺寸与更强的表型可塑性能够使个体在不同环境类型中获得更高的平均适合度，则该表型特征在基因流存在的情境下可能具备适应性意义。