Length parameter of each gene class.

The table showed that genes with more alternative promoters tend to have increased length in all aspects of gene structure parameter. SP means gene with single promoter while AP means gene with alternative promoters. AP = 2, AP = 3∼4, and AP> = 5 means gene with only 2 promoters, 3 or 4 promoters, and at least 5 promoters, respectively. a: Median length; b: Median count; c: Wilcoxon rank sum test, AP vs. SP. d: Wilcoxon rank sum test, AP = 2 vs. SP. e: Wilcoxon rank sum test, AP = 3∼4 vs. AP = 2. f: Wilcoxon rank sum test, AP> = 5 vs. AP = 3∼4. *: The Wilcoxon rank sum test function in R (wilcox.test) returns “P<2.2e-16” when P is smaller than 2.2e-16.