How do I represent circular DNA in WIPO ST.26, e.g. plasmids or mitochondrial/chloroplast genomes?
While there could be multiple ways to represent a circular DNA sequence in the context of WIPO ST.26, it is recommended that you include a “misc_feature” with a location x^1, where x is the last position (equal to the length) and a note qualifier indicating the molecule is circular. The qualifier “circular_RNA” can be used in very specific circumstances, with features such as CDS, mRNA, tRNA and other features that are produced as a result of a backsplicing event, when the splice event is indicated in the "join" operator, e.g., join(complement(69611..69724),139856..140087) (see ST.26 Annex 1, section 6.7).