DNA sequence variation and methylation in an arsenic tolerant earthworm population

Kille, Peter and Andre, Jane and Anderson, Craig and Ang, Hui Na and Bruford, Michael W. and Bundy, Jacob G. and Donnelly, Robert and Hodson, Mark E. and Juma, Gabriela and Lahive, Elma and Morgan, A. John and Sturzenbaum, Stephen R. and Spurgeon, David J. (2013) DNA sequence variation and methylation in an arsenic tolerant earthworm population. Soil Biology and Biochemistry, 57. pp. 524-532. ISSN 0038-0717

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Abstract

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 II, 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 naïve strain. COII 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.

Item Type:
Journal Article
Journal or Publication Title:
Soil Biology and Biochemistry
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/2400/2404
Subjects:
ID Code:
67953
Deposited By:
Deposited On:
11 Dec 2013 09:16
Refereed?:
Yes
Published?:
Published
Last Modified:
26 Oct 2020 02:39