Canadian Forest Service Publications
Using nested PCR to improve detection of earthworm eDNA in Canada. 2017. Jackson, M.; Myrholm, C.; Shaw, C.; Ramsfield, T. Soil Biology and Biochemistry 113 (2017):215-218.
Issued by: Northern Forestry Centre
Catalog ID: 38720
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Earthworms that are invasive to Canada's boreal forest are mainly from the family Lumbricidae and they have the potential to change ecosystem carbon sequestration and biodiversity. Traditional methods used to survey earthworms rely on finding specimens, consume large amounts of time and labour, and are expensive. A sensitive genetic method to detect earthworm DNA in soil would provide a fast, relatively low cost method for earthworm survey. In this study, PCR primers were used to detect earthworm DNA from earthworm tissues and soil samples. Though single PCR yielded only faint signals from soil samples, a nested PCR method allowed strong detection in native and cultivated forest soils, including those archived for more than 30 years, providing a promising technique for genetic monitoring of earthworms in the boreal region of Canada
Plain Language Summary
Earthworms are invasive species in Canada’s boreal forest and have the potential to change ecosystem biodiversity and carbon. Traditional methods used to survey earthworms rely on finding earthworm specimens; these methods consume large amounts of time and labour, and are expensive. A sensitive genetic method to detect earthworm DNA in soil would provide a fast, relatively low-cost method to survey earthworms. In this study, we used a common approach with genetic markers for earthworm tissues and soil samples that only detected a weak signal from soil samples. We then developed a method to increase the strength of the signal from small segments of DNA extracted from the commonly used method, which allowed strong detection from a variety of soil samples. This method provides a promising start for genetic monitoring of earthworms in the boreal region of Canada.