Table 1. Comparison of intron lengths.

Gened	N(genes)f	Aver1g	Aver-1h	L<exp(L)i	L = exp(L)j	L>exp(L)k	valuel
All e	19770	13732	4861	39.13	0.02	60.84	∼0
Housekeeping genes (HK)	414	5851	2136	36.75	0	63.25	3.6e–16
Blood (BD)	145	12340	4121	31.39	0	68.61	4.15e–9
Brain (BRA)	260	22986	7814	35.95	0	64.05	1.82e–12
Breast (BRE)	54	15447	12135	52.08	0	47.92	0.9942
Cervix (CX)	53	21039	5109	38.46	0	61.54	1.92e–6
Colon (CO)	37	22325	5605	51.43	0	48.57	3e–3
Endometrium (ENDO)	125	19587	5629	30.83	0	69.17	1.03e–11
Esophagus (ES)	111	15358	4290	33.96	0	66.04	2.96e–5
Kidney (KI)	550	17207	5760	36.55	0	63.45	3.9e–34
Liver (LI)	570	14167	4627	34.39	0	65.61	6.17e–35
Lung (LU)	610	15782	5030	33.56	0	66.44	4.91e–42
Muscle (MU)	513	15910	5269	36.36	0	63.64	1.29e–31
Myometrium (MY)	102	21346	5802	34.65	0	65.35	1.07e–7
Ovary (OV)	228	16622	4483	36.87	0	63.13	4.73e–20
Placenta (PL)	105	18213	4302	37.76	0	62.24	7.87e–8
Prostate (PR)	624	16970	5504	35.85	0	64.15	8.2e–41
Stomach (ST)	31	36466	7048	24	0	76	5.37e–5
Spleen (SP)	24	13525	3173	27.27	0	72.73	1.21e–2
Testes (TE)	25	32527	8853	22.73	0	77.27	3.49e–1
Vulva (VU)	162	15179	3621	33.11	0	66.89	1.34e–11

d: the name of each group ;

e: all sample genes;

f: the number of genes in each group;

g: the average lengths (unit: bp) of the first introns;

h: the average lengths of the non-first introns;

i: the gene proportions observed with the first intron length shorter than their expected length;

j: the gene proportions observed with the first intron length equal to their expected length;

k: the gene proportions observed with the first intron length longer than their expected length;

l: the value of KS test.