The influence of intraspecific sequence variation during DNA metabarcoding: A case study of eleven fungal species

DNA metabarcoding has become a powerful approach for analyzing complex communities from environmental samples, but there are still methodological challenges limiting its full potential. While conserved DNA markers, like 16S and 18S, often are not able to discriminate among closely related species, other more variable markers – like the fungal ITS region, may include considerable intraspecific variation, which can lead to over-splitting of species during DNA metabarcoding analyses. Here we assess the effects of intraspecific sequence variation in DNA metabarcoding, by analyzing local populations of eleven fungal species. We investigated the allelic diversity of ITS2 haplotypes using both Sanger sequencing and high throughput sequencing (HTS) coupled with error correction with the software dada2. All focal species, except one, included some level of intraspecific variation in the ITS2 region. Overall, we observed a high correspondence between haplotypes generated by Sanger sequencing and ...