Table 1. Analysis of the representative features within the mRNAs in the different translation classes.

Feature analyzed	Class I	Class II	Class III
Number of mRNAs	696	14946	456
cDNA length (nts)	1204*	1641*	2323*
CDS length (nts)	857*	1279*	1981*
5′-UTR length (nts)	121	139	126
5′-UTR G+C content (%)	42.33*	37.61*	36.07*
5′-UTR (1–10) G+C content (%)	40.2*	36.3*	35.3*
5′-UTR ΔG (kcal/mol)	−21.13	−22.07	−18.63
3′-UTR length (nts)	226	223	216
3′-UTR G+C content (%)	32.29	31.64	31.02
3′-UTR ΔG (kcal/mol)	−40.69	−39.91	−37.49
uAUG ≥1 (%)	24.57	32.18	30.92
uAUG ≥2 (%)	11.21	15.84	14.47
uAUG ≥3 (%)	6.18	8.66	6.36
uAUG ≥4 (%)	3.59	5.09	3.73

Data sets for the indicated parameters of the representative gene models (n = 16098) were retrieved and analyzed as stated in Materials and Methods. Values are expressed as medians or as percentage when stated. Cumulative curves were plotted separately for all the features analyzed (data not shown). K–S test was used to validate the variations in the distribution of the individual features among the established groups, using Class II as reference. Statistically significant differences, with correlation with the relative translation efficiency, were highlighted by an asterisk (p<0.001).