Coming of age for COI metabarcoding of whole organism community DNA:
towards bioinformatic harmonisation
Abstract
Metabarcoding of DNA extracted from community samples of whole organisms
(whole organism community DNA, wocDNA) is increasingly being applied to
terrestrial, marine and freshwater metazoan communities to provide
rapid, accurate and high resolution data for novel molecular ecology
research. The growth of this field has been accompanied by considerable
development that builds on microbial metabarcoding methods to develop
appropriate and efficient sampling and laboratory protocols for whole
organism metazoan communities. However, considerably less attention has
focused on ensuring bioinformatic methods are adapted and applied
comprehensively in wocDNA metabarcoding. In this study we examined over
600 papers and identified 111 studies that performed COI metabarcoding
of wocDNA. We then systematically reviewed the bioinformatic methods
employed by these papers to identify the state-of-the-art. Our results
show that the increasing use of wocDNA COI metabarcoding for metazoan
diversity is characterised by a clear absence of bioinformatic
harmonisation, and the temporal trends show little change in this
situation. The reviewed literature showed (i) high heterogeneity across
pipelines, tasks and tools used, (ii) limited or no adaptation of
bioinformatic procedures to the nature of the COI fragment, and (iii) a
worrying underreporting of tasks, software and parameters. Based upon
these findings we propose a set of recommendations that we think the
wocDNA metabarcoding community should consider to ensure that
bioinformatic methods are appropriate, comprehensive and comparable. We
believe that adhering to these recommendations will improve the
long-term integrative potential of wocDNA COI metabarcoding for
biodiversity science.