Table 2 The Spearman’s coefficient of correlation (ρ) between exon length and the d _N / d _S ratio, d _N , and d _S before (upper row; “Original”) and after (lower row; “Control”) controlling for four potential confounding factors (ASE/CSE exon type, proprtion of repetitive elements/disordered regions, and exonic expression level)

From: The evolution of the coding exome of the Arabidopsisspecies - the influences of DNA methylation, relative exon position, and exon length