Library construction primer sequences.

AFor all primers sets, the 16S template specific sequences are given in bold. For the 454 primers, the Xs in the forward represent the 5 bp run-key defined by the MBL with the underlined portion representing the 454 Lib A (forward primer) or Lib B (reverse primers) adapter sequence. Underlined portions of the Illumina primers represent the full TruSeq adapter sequence (V4-V5 primers) or a truncated version (V4). The N-bases in italics for the V4-V5 primers represent the 4 base ambiguous mix in between the TruSeq adapter sequence and the 16S template sequence. The Xs in the V4-V5 forward primer represent the sequence of one of the 6 bp TruSeq indices defined by Illumina while in the V4 forward primer they represent the 12 base Golay encoding barcode as defined by Caporaso et al.