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.

极端灾害事件为研究自然环境中种群对胁迫的快速响应提供了独特契机。与遗传变异协同发挥作用的表观遗传机制（epigenetic mechanisms，如DNA甲基化（DNA methylation）），可为面临严峻环境挑战的生物提供快速响应途径，并助力互花米草（Spartina alterniflora）这类建群性盐沼草本展现出对强烈环境扰动的高耐受能力。2010年，深水地平线（Deepwater Horizon）漏油事件重创了墨西哥湾沿岸大片海岸线。事件发生后，我们同步研究了受油污暴露的互花米草恢复种群的遗传与表观遗传结构。我们采用扩增片段长度多态性（Amplified Fragment Length Polymorphism, AFLP）与甲基化敏感扩增片段长度多态性（Methylation-Sensitive Amplified Fragment Length Polymorphism, MS-AFLP）技术对遗传变异与DNA甲基化变异进行量化，以验证"互花米草对油污暴露的响应会产生基于遗传与表观遗传机制的种群分化"这一假说。研究发现，各采样点内部及不同采样点间均存在较高水平的遗传与表观遗传变异，且受污染与未受污染样地间存在显著的遗传分化，这或反映了针对油污暴露的非随机性死亡事件。此外，尽管受污染与未受污染样地间未出现全基因组范围的DNA甲基化模式差异，但我们发现有5个MS-AFLP位点（占多态性MS-AFLP位点总数的12%）与油污暴露显著相关。总体而言，本研究结果证实了该系统中与油污暴露相关的遗传分化，同时也表明表观遗传机制可能在种群分化中发挥潜在作用。