Protocol for PCR amplification of extracted cDNA or DNA and downstream library preparation for MiSeq sequencing.See other related protocols for extraction of RNA and/or DNA from environmental samplesThis protocol is specific to 18S rRNA gene tag sequencing targeting to V4 hypervariable region. We use V4 primers with Illumina adapters that then anneal to the P5 & P7 Illumina-specific indices. This barcoding step allows us to multiplex many samples for MiSeq sequencing. The V4 region is ~400bp, so we typically do MiSeq 250x250bp PE sequencing.