2.2. Pre-processing
The sequence quality was checked with FastQC tool[20] and the minimum base per quality for future
analysis was fixed as PHRED >25. Based on the QC, high
rates of erroneous sequences from Illumina, 454 and Ion Torrent files
(Table 1) were removed further from the meta-analysis. The two major
reasons for the exclusion are 1) erroneous sequences (of PHRED
<25) and 2) Short reads (<200 bps) screened by DADA2[21] while picking sub-Operational Taxonomic Units
(s-OTUs). Overall, Illumina sequences contained better quality than the
Ion-torrent and Pyrosequence Finally, we carried out a meta-analysis
with 452 files of copepods associated bacteriobiome to test the proposed
hypothesis.