Figure 4.

Left. Distribution of the differences between the mean sequence length of the overlapping genes and the mean sequence length of their orthologues that do not overlap. The set is comprised of the 290 COGs for which a t test rejects the null hypothesis that the mean length is equal in the two sets (overlapping and non overlapping). Right. Distribution of the differences between the standard deviations of the lengths of the overlapping genes and of the standard deviation of the lengths of the orthologous genes that do not overlap.