Table 1.

Properties of retained and constitutive introns. For all intron parameters the medians are reported. The last two columns report the statistical significance of the differences of the distributions by the Kolmogorov-Smirnov test (KS) and Student's t-test (ST); n/s – non significant.

	introns
	Retained	Constitutively spliced	KS	ST
Set size	1197	137580
Intron length (nucleotides)	337	1481	<10-15	<10-15
Splice site scores
Acceptor site of the of 5'-exon	18,60	19,09	<10-15	<10-11
Donor site	18,17	18,80	<10-15	<10-15
Acceptor	18,03	19,06	<10-15	<10-15
Donor site of 3'-exon	18,74	18,79	n/s	n/s
Cis-acting elements (candidate sites per nucleotie)
ESEfinder: SC35	0,046	0,034	<10-15	<10-15
ESEfinder: SF2/ASF	0,040	0,028	<10-15	<10-15
ESEfinder: SRp40	0,041	0,038	<10-15
ESEfinder: SRp55	0,022	0,022	<10-15	n/s
RESCUE-ESE	0,050	0,068	<10-15	<10-15
PESE	0,043	0,035	<10-15	<10-15
PESS	0,013	0,048	<10-15	<10-15
Relative position
by ordinal number	0,6	0,5	<10-15*	<10-15
by gene	0,671	0,597	<10-9	<10-15
by mRNA	0,446	0,354	<10-15	<10-15
by mRNA w/o last exon	0,688	0,575	<10-15	<10-15

* Chi-square test