Comparative Analysis of Human Gut Microbiota by Barcoded Pyrosequencing (original) (raw)
Figure 1
Variability within the 16S rRNA gene.
From pre-aligned sequenced >1200 bp downloaded from RDP, the variability, measured as Shannon information entropy, was calculated at each sequence position, using only positions without a gap in E. coli. The graph shows the Shannon entropy (y-axis) averaged over 50 bp windows, centered at each position in the gene (x-axis). Shannon entropy at position x was calculated as –Σ p(xi) log_2 p_(xi), where p(xi) denotes the frequency of nucleotide i. The filled arrows indicate positions of the PCR primers, the dashed arrow the direction of sequencing.