Figure S2.
In panel A, the box plot compares intron lengths between humans and viruses. Human introns are significantly longer than viral introns, as indicated by four asterisks above the comparison bracket. The y-axis is labeled Intron length and ranges up to approximately 12,000. Human introns show a much wider distribution and higher median compared to viral introns, which are shorter and more tightly distributed. The figure indicates statistical significance but does not specify the test in the image. In panel B, the scatter plots show the relationship between observed minimum folding energy (M F E) and mean M F E of the shuffled ensemble for three transcript regions: 3 prime U T R, 5 prime U T R, and Exon. The x-axis represents Observed M F E, and the y-axis represents Mean M F E of the shuffled ensemble. Each plot contains many data points clustered along a diagonal reference line (y equals x). The correlation coefficients (r squared) are 0.9 for 3 prime U T R, 0.92 for 5 prime U T R, and 0.88 for Exon, indicating strong positive correlations between observed and shuffled M F E values.
Comparison of viral and human intron lengths and secondary structure in human transcripts. (A) Viral introns are shorter than human introns. P value was from t test, ****P < 0.0001. (B) Transcript regions exported to the cytoplasm possess secondary structure in line with random expectation. For human 3′ UTRs, 5′ UTRs, and exons, each region’s observed MFE is plotted against the mean MFE derived from the region’s shuffled ensemble described in Fig. 1 D.