DOI: 10.5061/dryad.64687
title: Data from: Tag jumps illuminated – reducing sequence-to-sample misidentifications in metabarcoding studies

description: Metabarcoding of environmental samples on second-generation sequencing
 platforms has rapidly become a valuable tool for ecological studies. A
 fundamental assumption of this approach is the reliance on being able to
 track tagged amplicons back to the samples from which they originated. In
 this study, we address the problem of sequences in metabarcoding
 sequencing outputs with false combinations of used tags (tag jumps).
 Unless these sequences can be identified and excluded from downstream
 analyses, tag jumps creating sequences with false, but already used tag
 combinations, can cause incorrect assignment of sequences to samples and
 artificially inflate diversity. In this study, we document and investigate
 tag jumping in metabarcoding studies on Illumina sequencing platforms by
 amplifying mixed-template extracts obtained from bat droppings and leech
 gut contents with tagged generic arthropod and mammal primers,
 respectively. We found that an average of 2.6% and 2.1% of sequences had
 tag combinations, which could be explained by tag jumping in the leech and
 bat diet study, respectively. We suggest that tag jumping can happen
 during blunt-ending of pools of tagged amplicons during library build and
 as a consequence of chimera formation during bulk amplification of tagged
 amplicons during library index PCR. We argue that tag jumping and
 contamination between libraries represents a considerable challenge for
 Illumina-based metabarcoding studies, and suggest measures to avoid false
 assignment of tag jumping-derived sequences to samples.
description: LD1_Read1.fastqRaw sequences, Leech diet study, Pool 1, Read 1.TOG-3LX3-A3_S4_L001_R1_001.fastq.gzLD1_Read2.fastqRaw sequences, Leech diet study, Pool 1, Read 2.TOG-3LX3-A3_S4_L001_R2_001.fastq.gzLD2_Read1.fastqRaw sequences, Leech diet study, Pool 2, Read 1.TOG-3LX3-A4_S5_L001_R1_001.fastq.gzLD2_Read2.fastqRaw sequences, Leech diet study, Pool 2, Read 2.TOG-3LX3-A4_S5_L001_R2_001.fastq.gzLD3_Read1.fastqRaw sequences, Leech diet study, Pool 3, Read 1.TOG-3LX3-A5_S8_L001_R1_001.fastq.gzLD3_Read2.fastqRaw sequences, Leech diet study, Pool 3, Read 2.TOG-3LX3-A5_S8_L001_R2_001.fastq.gzLD4_Read1.fastqRaw sequences, Leech diet study, Pool 4, Read 1.TOG-3LX3-A6_S10_L001_R1_001.fastq.gzLD4_Read2.fastqRaw sequences, Leech diet study, Pool 4, Read 2.TOG-3LX3-A6_S10_L001_R2_001.fastq.gzLD5_Read1.fastqRaw sequences, Leech diet study, Pool 5, Read 1.TOG-3LX3-A7_S13_L001_R1_001.fastq.gzLD5_Read2.fastqRaw sequences, Leech diet study, Pool 5, Read 2.TOG-3LX3-A7_S13_L001_R2_001.fastq.gzLD6_Read1.fastqRaw sequences, Leech diet study, Pool 6, Read 1.TOG-3LX3-A9_S16_L001_R1_001.fastq.gzLD6_Read2.fastqRaw sequences, Leech diet study, Pool 6, Read 2.TOG-3LX3-A9_S16_L001_R2_001.fastq.gzBD1_Read1.fastqRaw sequences, Bat diet study, Pool 1, Read 1TOG-TYYP-Japan5_S8_L001_R1_001.fastq.gzBD1_Read2.fastqRaw sequences, Bat diet study, Pool 1, Read 2TOG-TYYP-Japan5_S8_L001_R2_001.fastq.gzBD2_Read1.fastqRaw sequences, Bat diet study, Pool 2, Read 1TOG-TYYP-Japan2_S5_L001_R1_001.fastq.gzBD2_Read2.fastqRaw sequences, Bat diet study, Pool 2, Read 2TOG-TYYP-Japan2_S5_L001_R2_001.fastq.gzBD3_Read1.fastqRaw sequences, Bat diet study, Pool 3, Read 1TOG-TYYP-Japan3_S6_L001_R1_001.fastq.gzBD3_Read2.fastqRaw sequences, Bat diet study, Pool 3, Read 2TOG-TYYP-Japan3_S6_L001_R2_001.fastq.gzBD4_Read1.fastqRaw sequences, Bat diet study, Pool 4, Read 1TOG-TYYP-Japan4_S7_L001_R1_001.fastq.gzBD4_Read2.fastqRaw sequences, Bat diet study, Pool 4, Read 2TOG-TYYP-Japan4_S7_L001_R2_001.fastq.gzBD5_Read1.fastqRaw sequences, Bat diet study, Pool 5, Read 1TOG-TYYP-Japan1_S4_L001_R1_001.fastq.gzBD5_Read2.fastqRaw sequences, Bat diet study, Pool 5, Read 2TOG-TYYP-Japan1_S4_L001_R2_001.fastq.gzTags_in_librariesSheet 1: List of tags used in libraries (LD1-LD6 and BD1-BD5); Sheet 2: List of tag-sequences in the leech diet study; Sheet 3: List of tag-sequences in the bat diet study.