Fig. 5
From: The unusual gene architecture of polyubiquitin is created by dual-specific splice sites
Introns in tandem repeats could suggest an evolutionary mechanism for de novo intron creation. a Illustrated example of an intron (blue line) in a tandem repeat (yellow) whose length is a multiple of the repeat unit’s length. b Enrichment of introns that splice via DSSs (permutation test, see Methods). c Comparison between two models of de novo intron creation in a tandem repeat: the DSS expansion model (1) and the 2-hit model (2). Arrows indicate evolutionary change. Probabilities of motif creation and repeat expansion taken from Conrad et al. [37] and Fan and Chu [38]