Ni Ping, Li Shiguo, Lin Yaping, Xiong Wei, Huang Xuena, Zhan Aibin
Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing China.
University of Chinese Academy of Sciences Chinese Academy of Sciences Beijing China.
Ecol Evol. 2018 Sep 5;8(20):10272-10287. doi: 10.1002/ece3.4504. eCollection 2018 Oct.
The geographical expansion of invasive species usually leads to temporary and/or permanent changes at multiple levels (genetics, epigenetics, gene expression, etc.) to acclimatize to abiotic and/or biotic stresses in novel environments. Epigenetic variation such as DNA methylation is often involved in response to diverse local environments, thus representing one crucial mechanism to promote invasion success. However, evidence is scant on the potential role of DNA methylation variation in rapid environmental response and invasion success during biological invasions. In particular, DNA methylation patterns and possible contributions of varied environmental factors to methylation differentiation have been largely unknown in many invaders, especially for invasive species in marine systems where extremely complex interactions exist between species and surrounding environments. Using the methylation-sensitive amplification polymorphism (MSAP) technique, here we investigated population methylation structure at the genome level in two highly invasive model ascidians, and collected from habitats with varied environmental factors such as temperature and salinity. We found high intrapopulation methylation diversity and significant population methylation differentiation in both species. Multiple analyses, such as variation partitioning analysis, showed that both genetic variation and environmental factors contributed to the observed DNA methylation variation. Further analyses found that 24 and 20 subepiloci were associated with temperature and/or salinity in and , respectively. All these results clearly showed significant methylation divergence among populations of both invasive ascidians, and varied local environmental factors, as well as genetic variation, were responsible for the observed DNA methylation patterns. The consistent findings in both species here suggest that DNA methylation, coupled with genetic variation, may facilitate local environmental adaptation during biological invasions, and DNA methylation variation molded by local environments may contribute to invasion success.
入侵物种的地理扩张通常会导致多个层面（遗传学、表观遗传学、基因表达等）的暂时和/或永久性变化，以适应新环境中的非生物和/或生物胁迫。诸如DNA甲基化之类的表观遗传变异常常参与对多样的当地环境的响应，因此代表了促进入侵成功的一种关键机制。然而，关于DNA甲基化变异在生物入侵过程中快速环境响应和入侵成功方面的潜在作用，证据很少。特别是，在许多入侵物种中，尤其是在物种与周围环境之间存在极其复杂相互作用的海洋系统中的入侵物种，DNA甲基化模式以及各种环境因素对甲基化分化的可能贡献在很大程度上尚不清楚。利用甲基化敏感扩增多态性（MSAP）技术，我们在此研究了两种高度入侵性的模式海鞘和从具有不同环境因素（如温度和盐度）的栖息地收集的群体在基因组水平上的甲基化结构。我们发现这两个物种在种群内甲基化多样性都很高，且种群甲基化分化显著。多种分析，如变异分配分析，表明遗传变异和环境因素都对观察到的DNA甲基化变异有贡献。进一步分析发现，在和中分别有24个和20个亚表观位点与温度和/或盐度相关。所有这些结果清楚地表明，这两种入侵海鞘的种群之间存在显著的甲基化差异，并且不同的当地环境因素以及遗传变异是观察到的DNA甲基化模式的原因。这里在两个物种中一致的发现表明，DNA甲基化与遗传变异相结合，可能在生物入侵过程中促进当地环境适应，并且由当地环境塑造的DNA甲基化变异可能有助于入侵成功。
