Figure 1
From: Non-specific amplification of human DNA is a major challenge for 16S rRNA gene sequence analysis
Proposed mechanism for off target amplification of mammalian DNA by V3–V4 primers, as opposed to V1–V2. (A) DNA extracted from human biopsies is known to contain large proportions of human DNA. In these circumstances V3–V4 degenerate primers, which also align to region in human mitochondrial DNA as shown can bind and amplify human DNA. There is no such alignment for V1–V2 degenerate primers. (B) Off target amplification significantly alters the 16S rRNA gene sequencing profile of a sample.
