DNA sequence variation and methylation in an arsenic tolerant earthworm population
DNA sequence variation and methylation in an arsenic tolerant earthworm population
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DOI：
10.1016/j.soilbio.2012.10.014
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发表时间：
2013-02-01
影响因子：
9.7
通讯作者：
Spurgeon, David J.
中科院分区：
文献类型：
--
作者：
Kille, Peter;Andre, Jane;Spurgeon, David J.
有证据表明蚯蚓能够对微量元素富集的土壤产生耐受性。然而，很少有研究试图确定这种耐受性是通过适应性还是可塑性决定的。在此，我们报告了对来自一个废弃砷铜矿场不同地点的红蚯蚓（Lumbricus rubellus）种群进行线粒体（细胞色素氧化酶COII）、核（扩增片段长度多态性，AFLP）变异以及DNA甲基化综合分析的结果。与原始品系相比，来自矿场种群的蚯蚓表现出明显的砷耐受性。COII和AFLP结果表明，来自未暴露和适应种群的红蚯蚓包含两个隐性谱系（谱系A和B），这两个谱系在所有地点都存在。按谱系进行的AFLP分析突出了与土壤金属/类金属浓度相关的变异（对于谱系A最为明显），这表明观察到的耐受性存在遗传成分。甲基化敏感AFLP（Me - AFLP）在两个谱系中都鉴定出较高的基因组甲基化含量（平均13.5%）。对于谱系A，Me - AFLP分析未发现与土壤砷含量有很强的关联。然而，对于谱系B，发现甲基化模式与土壤砷浓度有明显关联。这表明谱系B的蚯蚓利用表观遗传机制来适应污染的存在。这两个分支中根本不同的遗传调整表明，两个谱系在应对砷暴露时采用了不同的适应策略（遗传或表观遗传）。导致这种变异的机制可能基于谱系的定殖历史。（C）2012爱思唯尔有限公司。保留所有权利。
Evidence is emerging that earthworms can evolve tolerance to trace element enriched soils. However, few studies have sought to establish whether such tolerance is determined through adaptation or plasticity. Here we report results from a combined analysis of mitochondrial (cytochrome oxidase COII), nuclear (amplified fragment length polymorphism, AFLP) variation and DNA methylation in populations of the earthworm Lumbricus rubellus from sites across an abandoned arsenic and copper mine. Earthworms from the mine site population demonstrated clear arsenic tolerance in comparison to a nave strain. COIL and AFLP results suggest that L rubellus from the unexposed and the adapted populations comprises two cryptic lineages (Lineages A and B) each of which was present across all of the sites. AFLP analysis by lineage highlighted variations associated with soil metal/metalloid concentrations (most clearly for Lineage A) suggesting a genetic component to the observed tolerance. The methylation sensitive AFLP (Me-AFLP) identified a high genome methylation content (average 13.5%) in both lineages. For Lineage A, Me-AFLP analysis did not identify a strong association with soil arsenic levels. For Lineage B, however, a clear association of methylation patterns with soil arsenic concentrations was found. This suggests that Lineage B earthworms utilise epigenetic mechanisms to adapt to the presence of contamination. These fundamentally different genetic adjustments in the two clades indicate that the two lineages employ distinct adaptive strategies (genetic or epigenetic) in response to arsenic exposure. Mechanisms driving this variation may be founded within the colonisation histories of the lineages. (C) 2012 Elsevier Ltd. All rights reserved.