16S sequencing of positive control samples

Synthesized mock DNA samples were designed as positive control, named gene blocks. We selected DNA to synthesize using regions of the 16S rRNA gene in 8 archaeal species which would not normally be detected in experimental data because the sequences at the amplification primer binding sites in the archaeal V1V2 region do not match the bacterial V1V2 primers used. However, in the engineered sequences, correct bacterial 16S V1V2 primer bindings sites were added synthetically to archaeal controls, allowing amplification. This has the advantage that the output sequences can be worked up as for experimental samples and the archaeal sequences read out with no extra effort.