Table 1. Correlation between structural genomic parameters and both gene expression and expression.

Gene characteristics	Expression level		Expression breadth
	Microarray	MPSS	Microarray	MPSS
	DS-I	O-I	DS-EB_w0	O-EB_w0
	r	r	r	r
Gene length	−0.142*	−0.064*	0.136*	0.108*
5′ UTR length	−0.023†	0.030‡	0.154*	0.125*
CDS length	−0.164*	−0.125*	0.014	0.014 ns
Intron length	−0.022†	0.018§	0.174*	0.124*
Intron length_w0	−0.102*	0.014 ns	0.152*	0.141*
3′ UTR length	0.074*	0.141*	0.202*	0.178*
Number of exons	−0.079*	−0.015	0.132*	0.099*
Average exon length	−0.028*	−0.061*	−0.159	−0.084*
Number of introns	−0.079*	−0.015*	0.132*	0.099*
Number introns_w0	−0.099*	−0.016 ns	0.090*	0.099*
Average intron length	0.008 ns	0.045*	0.146*	0.042*
Average intron length_w0	0.003 ns	0.050*	0.060*	0.044*
Intron Density	0.007 ns	0.078*	0.188*	0.124*
Intron Density_w0	0.004 ns	0.078*	0.151*	0.124*

Data are presented both for oligo-array and MPSS assays. Statistical significances: ns = not significant; §P<0.05 †P<0.01; ‡P<0.001;*P<0.0001. Sample size of the correlations were comprised between n = 12051 and n = 14236. Note1. For this calculations, gene for which expression was zero were not considered to avoid potential problem arising from defective probes (Eisenberg and Levanon, 2003). Note2. For introns parameters, data are presented both considering and excluding (w0) genes without introns.