5' leader length distribution and leaderless mRNAs. The graph shows the distribution of the distances between the TSS and the translation start site of 437 annotated protein coding genes for which a distinct TSS could be assigned. Five leaderless genes could be identified where the TSS corresponds to the annotated translation start site. Six genes have very long leader sequences >400 nucleotides in length. For comparison, leader lengths of 320 Ctr genes are included (dashed grey line) from a previous study . Nt, nucleotides.