Figure 3.

Illustration of splicing event definitions. Transcripts $t_1,t_2,t_3$ imply subexons $s_1,\dots ,s_8$. Subexons are colored according to the event type the corresponding (novel) splice junction defines. In this example, mapping signature $(1,7)$ defines a classical exon skipping (ES) with respect to $t_3$, and a nonclassical ES wrt $t_2$. $(3,5)$ spans an alternative donor (AD) wrt $t_2$, $(4,6$) an alternative acceptor (AA) wrt $t_2$, $(5,8)$ an alternative donor-acceptor pair (AP) wrt $t_2$ and an alternative acceptor wrt $t_3$, $(1,3)$ a novel intron in exon (IE) wrt $t_2$, while the subexons $s_6$ and $s_7$ including the intron between them constitute a novel intron retention (IR)