APPRIS identifies a principal isoform for the majority of human genes. APPRIS determines a principal isoform for 17 731 (85.7%) of the 20 687 protein-coding genes in the GENCODE 7 (Ensembl 62) release (Supplementary Figure S4). A total of 53 307 variants were tagged as alternative by the methods in APPRIS and 22 799 transcripts were identified as principal isoforms (the discrepancy between genes and transcripts is because many transcripts are only alternatively spliced in the 3′- or 5′-regions and are regarded as identical by APPRIS because they have identical coding sequences).
