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DNA matching exotic species detected in samples from sedentary birds and the environment
  • +3
  • Coen Westerduin,
  • Marko Suokas,
  • Tuukka Petäjä,
  • Ulla Saarela,
  • Seppo Vainio,
  • Marko Mutanen
Coen Westerduin
University of Oulu

Corresponding Author:[email protected]

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Marko Suokas
University of Oulu Faculty of Science
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Tuukka Petäjä
University of Helsinki
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Ulla Saarela
University of Oulu
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Seppo Vainio
University of Oulu
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Marko Mutanen
University of Oulu
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The development of DNA-based methods in recent decades has opened the door to numerous new lines of research in the biological sciences. While their speed and accuracy are clearly beneficial, the sensitivity of these methods has the adverse effect of increased susceptibility to false positives resulting from contamination in field or lab. Here, we present findings from a metabarcoding study on the diet of and food availability for several insectivorous birds, in which multiple lepidopteran species not known to occur locally were discovered. After describing the pattern of occurrences of these non-local species in the samples, we discuss various potential origins of these sequences. First, we assess that the taxonomic assignments appear reliable, and local occurrences of many of the species can be plausibly ruled out. Then, we look into the possibilities of natural environmental contamination, judging it to be unlikely, albeit impossible to fully falsify. Finally, while the pattern of occurrences did not suggest lab contamination, we find overlap with material handled in the same lab, which was undoubtedly not coincidental. Even so, not all exact sequences were accounted for in these locally conducted studies, nor was it clear if these and other sequences could remain detectable years later. Although the full explanation for the observations of non-local species remains inconclusive, these findings highlight the importance of critical examination of metabarcoding results, and showcase how species-level taxonomic assignments utilizing comprehensive reference libraries may be a tool in detecting potential contamination events, and false positives in general.
14 Mar 2023Submitted to Ecology and Evolution
16 Mar 2023Submission Checks Completed
16 Mar 2023Assigned to Editor
16 Mar 2023Reviewer(s) Assigned
03 May 2023Review(s) Completed, Editorial Evaluation Pending
17 May 2023Editorial Decision: Revise Minor
26 Sep 20231st Revision Received
26 Sep 2023Submission Checks Completed
26 Sep 2023Assigned to Editor
26 Sep 2023Review(s) Completed, Editorial Evaluation Pending
04 Oct 2023Editorial Decision: Accept