Fig. 2

Novel transcripts description. A Schematic representation of different types of newly identified transcripts, which result from alternative splicing events that lead to intron retentions (i), exon extensions (ii), novel exon inclusion (iii), exon skipping (iv) and exon shortening (v). Example of a connection between two transcriptional units is represented by isoform (vi) that connects Gene 1 and 2. B Relative contribution to overall gene expression by annotated and novel IRD transcripts. X axis, relative contribution (in %) of gene expression in bins of 10, Y axis, number of IRD genes. C Structural classification of novel HEITs (highly expressed IRD transcripts). New exons are the most predominant feature, followed by intron retentions, while exon shortenings are the least common events