Microbial abundance in CRC and unaffected control gut mucosa tissue measured by RNA-Seq. (A) Phylogenetic abundance inferred from unique metatranscriptomics read pair mapping. Genera (n = 57) comprising, collectively, 99% of the microbial sequence data are shown. Values presented are the mean percent abundance ± SE, on a log10 scale. Genera are ordered top to bottom by decreasing read pair abundance in control tissue. The names of genera nominally over-represented in tumor (P <0.05) are red, and the names of genera nominally under-represented in tumor (P <0.05) are green. Genera indicated with an asterisk are significantly over-represented in tumor samples after multiple hypothesis testing correction (q <0.05); (B) Species distribution of uniquely mapped Fusobacterium, Leptotrichia, Campylobacter and Selenomonas normalized sequence pairs.