Figure 1.

How TEs affect the human and mouse transcriptome. (a) Summary of the effect of (i) exonization of TEs on the transcriptome; of the effect of exonization that (ii) creates an alternatively skipped exon, (iii) transforms an existing exon to an alternative 5'ss exon, or (vi) transforms an existing exon to an alternative 3'ss exon; or of the effect of exonization that (v) creates a constitutively spliced exon. The table on the right shows the corresponding numbers of transposed elements (TEs). (b) Summary of the effect of TE insertions in the first or last exon. Panel i shows the insertion of TEs (gray box) into an exon (white box). The insertion of the TEs can cause an enlargement of the first or last exon (panels ii and iii), or, in some cases, activates intronization (generating an alternatively spliced intron that splits the last exon into two smaller exons; panel iv). The numbers of those events according to TE family are shown on the right-hand side.