B Alignment of Sa19 and mitochondrial 16S rRNA Sa19 "like" segment (mt, mitochondrial; PTL, peptidyl transferase loop; D, domain; _, transition region) sequence with common core motif (blue) and uracils (red U); *, conserved in human (Hs), cattle (Bt), mouse and rat; G/A underlined, mutated core motif; ma, 6N methylation of adenosine 7. 