Fig. 4. Gene and ORF overlap across prokaryotes, eukaryotes and their viruses.

a | Escherichia coli menaquinone biosynthesis operon contains three short stop–start coding sequence (CDS) overlaps. b | The large human gene NF1 and internal nested protein-coding ORFs OMG, EVI2B and EVI2A are located within NF1 introns. c | Recently described alt-RPL36 (bottom) overlaps the human ribosomal protein gene RPL36 (ref.⁶⁵) through an out-of-frame GTG start codon within a 5′-extended RPL36 exon present on RPL36 transcript variant 2. The alt-RPL36 CDS generates a longer protein with an entirely different sequence from RPL36 (ref.⁶⁵). d | The virus φX174 contains overlaps in all three reading frames: three short unidirectional stop–start CDS overlaps, two nested CDSs, and one in-frame start generating an N-terminally trunkated protein.