Table 1. The growth of data hosted by the R-loopDB since the initial release.

	Initial release in 2012	Up-to-date in 2016
Gene annotation system	UCSC known genes	Ensembl build 75
No. of organisms	1 species	8 species
No. of transcript IDs	39 720	286 584
No. of gene IDs	14 954	121 056
No. of RLFSs in the human genes	245 181	511 651
No. of RLFS-merged regions in the human genes	140 106	169 222
No. of RLFSs in genes	245 181	1 565 795
No. of RLFS-merged regions in genes	140 106	565 789

Remark: the initial release database provides RLFSs only in genic regions, where the updated database provides RLFSs in genic regions and 2 kb up/downstream region of genes.