Simulation results on testing the difference between the distributions of length ratios of short vs. long genes for the two types of overlapping genes and the non-overlapping neighboring genes from the 13,484 genes. The X-axis is labeled with the first letter of the species name and the first letter of same- or different-strand (e.g., Hs and Hd refer to same- and different-strand in human respectively). The points are the observed means of length ratios of short vs. long genes. The bar inside each box marks the mean of 10,000 simulations. The whiskers mark the range of mean ratios in 10,000 simulations. The p-values are 0.0006 for mouse different-strand (Md), and the rest are all close to 0.