*2.3. RNA Editing Sites*

RNA editing features a set of processes that comprise of insertion, deletion or modifications of nucleotides that alter the DNA-encoded sequence [53], which represents a way to create transcript and protein diversity [54]. Some chloroplast RNA editing sites are preserved in plants [55]. The RNA editing sites in the *C. farinosa, C. glandulosa, M. crassifolia* and *M. oblongifolia* chloroplast genomes were predicted using the PREP suite program; the first codon position of the first nucleotide was used in all of the analyses. The results show that conversion of the amino acid serine into leucine was the majority of the conversions in the codon positions (Tables S5–S8). This conversion is found to occur more frequently [56]. In total, 48 editing sites in the genus *Maerua* and 50 in the genus *Cadaba* were revealed by the program. Twenty protein-coding genes in *C. farinosa* and 19 protein-coding genes in *C. glandulosa*, *M. crassifolia* and *M. oblongifolia* were distributed across the editing sites. As stated in previous studies [57–59], the *ndhB* genes have the largest number of editing sites (nine sites), followed by *ndhD* (nine sites in *C. farinosa* and *M. oblongifolia* and eight sites in *C. glandulosa* and *M. crassifolia*), while *accD, atpF*, *ccsA, clpP, PsaI, psbG, psbF, rpoA, rpl20, rps2 and rps16* have at least one site each. Certain RNA sites, amidst all the conversions in the RNA editing (modification) sites, changed the amino acid from proline to serine. RNA-predicting sites in the first codon of the first nucleotides are not present in the following genes: *atpA, atpB, atpI, ccsA* (only in *C. glandulosa*), *petB, petD, petG, petL, psaB, psbB, psbL, rpl2, rpl20* (except in *M. oblongifolia*), *rpl23, rps8 and ycf3,* among others. This result indicated that the preservation of RNA editing is fundamental [60,61].
