Overview of the transcript-to-CDS matches in NMDtxDB. If transcripts in the transcriptome match to mRNA in the Ensembl annotation, we name these matches as canonical. For novel transcripts or not annotated as mRNA, we use the start codon information from the sources to find a CDS. These may provide multiple CDS per transcript; however, if the CDS is identical, we keep a single hit. The is_PTC flag is TRUE if the distance from the stop codon and the last EJC exceeds 50 nt. Of note, the transcripts in the same_intron_chain class have proportionally less PTC calls for all sources. In contrast, the splicing_variants class has a similar number of transcripts with and without PTC for the riboseq and openprot sources.
