5_2_w
Library construction followed standard 2-step Illumina paired end sequencing techniques for short marker fragments. That is, a cocktail of universal bacterial PCR primers were used at a target length such that paired ends were fully overlapping. PCR was conducted in 2 steps, first (25 cycle) with universal primers only, and second step (5 cycle) where primers containing adaptor and barcode sequences were used to add these short Illumina-specific nucleotide fragments to each amplicon.