Data from: Genetic and epigenetic variation in Spartina alterniflora following the Deepwater Horizon oil spill

Catastrophic events offer unique opportunities to study rapid population response to stress in natural settings. In concert with genetic variation, epigenetic mechanisms like DNA methylation may offer a mechanism of rapid response to organisms facing severe environmental challenges, and contribute to the high resilience of species like Spartina alterniflora, a foundation salt marsh grass which shows resilience to strong environmental disturbance. In 2010, the Deepwater Horizon oil spill devastated large portions of the coastline along the Gulf of Mexico. Following the spill, we simultaneously examined the genetic and epigenetic structure of recovering populations of S. alterniflora to oil exposure. We quantified genetic and DNA methylation variation using AFLP and MS-AFLP to test the hypothesis that response to oil exposure in S. alterniflora resulted in genetically and epigenetically based population differentiation. We found high genetic and epigenetic variation within and among sites, and found significant genetic differentiation between contaminated and uncontaminated sites, which may reflect non-random mortality in response to oil exposure. Additionally, despite a lack of genome wide patterns in DNA methylation between contaminated and uncontaminated sites, we found five MS-AFLP loci (12% of polymorphic MS-AFLP loci) that were correlated with oil exposure. Overall, our findings support genetically based differentiation correlated to exposure to the oil spill in this system, but also suggest a potential role for epigenetic mechanisms in population differentiation.灾难性事件为研究自然环境中生物种群对胁迫的快速响应提供了独特契机。与遗传变异协同作用的表观遗传机制（epigenetic mechanisms），如DNA甲基化（DNA methylation），或许可为遭遇极端环境挑战的生物提供快速响应途径，并助力互花米草（Spartina alterniflora）这类盐沼建群草本物种展现出较强抗干扰能力——该物种对剧烈环境扰动具备良好耐受性。2010年，深水地平线（Deepwater Horizon）漏油事件重创了墨西哥湾沿岸的大片海岸线。漏油事件发生后，我们同步针对受原油暴露影响的互花米草恢复种群的遗传与表观遗传结构展开了研究。我们采用扩增片段长度多态性（AFLP）与甲基化敏感扩增片段长度多态性（MS-AFLP）对遗传变异及DNA甲基化变异进行定量分析，以验证如下假说：互花米草对原油暴露的响应，会引发基于遗传与表观遗传机制的种群分化。研究发现，各采样位点内部及位点间均存在较高水平的遗传与表观遗传变异；同时污染位点与未污染位点间存在显著的遗传分化，这或许反映了生物在原油暴露下发生的非随机死亡。此外，尽管污染与未污染位点间未检测到全基因组范围的DNA甲基化模式差异，但我们鉴定出5个与原油暴露显著相关的MS-AFLP位点（占多态性MS-AFLP位点总数的12%）。总体而言，本研究结果支持该系统中与漏油暴露相关的遗传分化假说，同时也暗示表观遗传机制在种群分化中可能发挥潜在作用。