Oke K B, Bukhari M, Kaeuffer R, Rolshausen G, Räsänen K, Bolnick D I, Peichel C L, Hendry A P
Redpath Museum and Department of Biology, McGill University, Montreal, QC, Canada.
Department of Aquatic Ecology, Eawag and Institute of Integrative Biology, ETH-Zurich, Duebendorf, Switzerland.
J Evol Biol. 2016 Jan;29(1):126-43. doi: 10.1111/jeb.12767. Epub 2015 Oct 16.
Parallel (and convergent) phenotypic variation is most often studied in the wild, where it is difficult to disentangle genetic vs. environmentally induced effects. As a result, the potential contributions of phenotypic plasticity to parallelism (and nonparallelism) are rarely evaluated in a formal sense. Phenotypic parallelism could be enhanced by plasticity that causes stronger parallelism across populations in the wild than would be expected from genetic differences alone. Phenotypic parallelism could be dampened if site-specific plasticity induced differences between otherwise genetically parallel populations. We used a common-garden study of three independent lake-stream stickleback population pairs to evaluate the extent to which adaptive divergence has a genetic or plastic basis, and to investigate the enhancing vs. dampening effects of plasticity on phenotypic parallelism. We found that lake-stream differences in most traits had a genetic basis, but that several traits also showed contributions from plasticity. Moreover, plasticity was much more prevalent in one watershed than in the other two. In most cases, plasticity enhanced phenotypic parallelism, whereas in a few cases, plasticity had a dampening effect. Genetic and plastic contributions to divergence seem to play a complimentary, likely adaptive, role in phenotypic parallelism of lake-stream stickleback. These findings highlight the value of formally comparing wild-caught and laboratory-reared individuals in the study of phenotypic parallelism.
平行（和趋同）表型变异大多是在野外进行研究的，而在野外很难区分遗传效应和环境诱导效应。因此，表型可塑性对平行性（和非平行性）的潜在贡献很少从正式意义上进行评估。如果可塑性导致野外种群间的平行性比仅由遗传差异所预期的更强，那么表型平行性可能会增强。如果特定地点的可塑性在原本遗传平行的种群间诱导出差异，那么表型平行性可能会受到抑制。我们对三对独立的湖 - 溪流棘鱼种群进行了共同花园实验研究，以评估适应性分化在多大程度上具有遗传或可塑性基础，并研究可塑性对表型平行性的增强和抑制作用。我们发现，大多数性状的湖 - 溪流差异具有遗传基础，但也有几个性状显示出可塑性的贡献。此外，可塑性在一个流域比在其他两个流域更为普遍。在大多数情况下，可塑性增强了表型平行性，而在少数情况下，可塑性具有抑制作用。遗传和可塑性对分化的贡献似乎在湖 - 溪流棘鱼的表型平行性中发挥着互补的、可能是适应性的作用。这些发现凸显了在表型平行性研究中正式比较野生捕获个体和实验室饲养个体的价值。
