Epigenetic variation reflects dynamic habitat conditions in a rare floodplain herb
Epigenetic variation reflects dynamic habitat conditions in a rare floodplain herb
复制标题
DOI：
10.1111/mec.12835
复制
发表时间：
2014-07
影响因子：
4.9
通讯作者：
B. Schulz;R. L. Eckstein;W. Durka
中科院分区：
文献类型：
--
作者：
B. Schulz;R. L. Eckstein;W. Durka
DNA甲基化的变异被认为在植物种群快速适应动态环境条件方面发挥着重要作用，从而补偿了遗传适应相对较慢的反应时间。然而，野生植物种群的遗传和表观遗传变异尚未在快速变化的环境中进行直接比较。在这里，我们沿着连续梯度调查了两个相邻栖息地类型的堇菜种群，其特征是光照可用性存在巨大差异。使用扩增片段长度多态性（AFLP）和甲基化敏感扩增多态性（MSAP）分析，我们发现遗传（H′gen = 0.19）和表观遗传（H′epi = 0.23）多样性水平相对较低，而遗传（ΦST = 0.72）和表观遗传（ΦST = 0.51）群体分化水平较高。多样性和分化显着相关，表明表观遗传变异部分取决于与遗传变异相同的驱动力。基于相关性的基因组扫描检测到与特定位点光可用性相关的遗传（17.0％）和表观遗传（14.2％）异常标记水平相当。然而，正如对 AFLP 的单独基于分化的基因组扫描所揭示的那样，似乎只有少数遗传标记实际上处于正选择之下（0-4.5%）。此外，主坐标分析和曼特尔测试表明，总体表观遗传变异与栖息地条件更为密切相关，表明环境引起的甲基化变化可能导致经历相似栖息地条件的种群趋同，因此可能在对不断变化的环境的短暂和/或遗传调整中发挥重要作用。此外，使用新的MSAP评分方法，我们发现表位点主要是非甲基化状态（ΦST = 0.60）和CG甲基化状态（ΦST = 0.46）有助于种群分化和假定的栖息地相关适应，而CHG半甲基化状态（ΦST = 0.21）仅发挥边缘作用。
Variation of DNA methylation is thought to play an important role for rapid adjustments of plant populations to dynamic environmental conditions, thus compensating for the relatively slow response time of genetic adaptations. However, genetic and epigenetic variation of wild plant populations has not yet been directly compared in fast changing environments. Here, we surveyed populations of Viola elatior from two adjacent habitat types along a successional gradient characterized by strong differences in light availability. Using amplified fragment length polymorphisms (AFLP) and methylation‐sensitive amplification polymorphisms (MSAP) analyses, we found relatively low levels of genetic (H′gen = 0.19) and epigenetic (H′epi = 0.23) diversity and high genetic (ϕST = 0.72) and epigenetic (ϕST = 0.51) population differentiation. Diversity and differentiation were significantly correlated, suggesting that epigenetic variation partly depends on the same driving forces as genetic variation. Correlation‐based genome scans detected comparable levels of genetic (17.0%) and epigenetic (14.2%) outlier markers associated with site specific light availability. However, as revealed by separate differentiation‐based genome scans for AFLP, only few genetic markers seemed to be actually under positive selection (0–4.5%). Moreover, principal coordinates analyses and Mantel tests showed that overall epigenetic variation was more closely related to habitat conditions, indicating that environmentally induced methylation changes may lead to convergence of populations experiencing similar habitat conditions and thus may play a major role for the transient and/or heritable adjustment to changing environments. Additionally, using a new MSAP‐scoring approach, we found that mainly the unmethylated (ϕST = 0.60) and CG‐methylated states (ϕST = 0.46) of epiloci contributed to population differentiation and putative habitat‐related adaptation, whereas CHG‐hemimethylated states (ϕST = 0.21) only played a marginal role.