Figure 4

Relative uORF compositional adaption to the translational machinery. Panel A shows the frequency histogram of log₂ ratios of uORF to principal ORF start codon adaption scores (AUG-CAI(r)). If a uORF is better adapted than the principal ORF, it will produce a positive log value. Panel B shows that same comparison considering the translation adpation index (tAI) of the complete reading frame in order to calculate the log₂ ratio. In both cases, uORFs are considerably less well adapted in general with log₂ mean values less than zero.