Eastern oysters in the northern Gulf of Mexico are facing rapid environmental changes and can respond to this change via plasticity or evolution. Plasticity can act as an immediate buffer against environmental change, but this buffering could impact the organism's ability to evolve in subsequent generations. While plasticity and evolution are not mutually exclusive, the relative contribution and interaction between them remains unclear. In this study, we investigate the roles of plastic and evolved responses to environmental variation and Perkinsus marinus infection in Crassostrea virginica by using a common garden experiment with 80 oysters from six families outplanted at two field sites naturally differing in salinity. We use growth data, P. marinus infection intensities, 3′ RNA sequencing (TagSeq) and low-coverage whole-genome sequencing to identify the effect of genotype, environment and genotype-by-environment interaction on the oyster's response to site. As one of first studies to characterize the joint effects of genotype and environment on transcriptomic and morphological profiles in a natural setting, we demonstrate that C. virginica has a highly plastic response to environment and that this response is parallel among genotypes. We also find that genes responding to genotype have distinct and opposing profiles compared to genes responding to environment with regard to expression levels, Ka/Ks ratios and nucleotide diversity. Our findings suggest that C. virginica may be able to buffer the immediate impacts of future environmental changes by altering gene expression and physiology, but the lack of genetic variation in plasticity suggests limited capacity for evolved responses.

中文翻译：

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缺乏基因型与环境的相互作用表明东部牡蛎（Crassostrea virginica）可塑性进化变化的潜力有限

墨西哥湾北部的东部牡蛎正面临着快速的环境变化，可以通过可塑性或进化来应对这种变化。可塑性可以作为对环境变化的直接缓冲，但这种缓冲可能会影响生物体在后代中进化的能力。虽然可塑性和进化并不相互排斥，但它们之间的相对贡献和相互作用仍不清楚。在这项研究中，我们通过对来自六个家庭的 80 只牡蛎在盐度自然不同的两个田间种植的普通花园实验，调查塑料和进化对环境变化和Perkinsus marinus感染的反应的作用。我们使用生长数据，P. marinus感染强度、3' RNA 测序 (TagSeq) 和低覆盖全基因组测序，以确定基因型、环境和基因型与环境的相互作用对牡蛎对位点反应的影响。作为在自然环境中表征基因型和环境对转录组和形态学特征的联合影响的首批研究之一，我们证明了C. virginica对环境具有高度可塑性的反应，并且这种反应在基因型之间是平行的。我们还发现，在表达水平、Ka/Ks 比率和核苷酸多样性方面，与对环境作出反应的基因相比，对基因型作出反应的基因具有不同和相反的特征。我们的研究结果表明，C. virginica 可能能够通过改变基因表达和生理学来缓冲未来环境变化的直接影响，但缺乏可塑性遗传变异表明进化反应的能力有限。