Table 2.

Distribution of Constrained Elements in the Human Genome

Rate^a	Count	Total length (bp)	Average size (bp)	% genome^b
Exonic segments
10%	43,031	3,810,697	88.56	0.13
20%	100,550	11,027,423	109.67	0.37
30%	131,940	18,755,479	142.15	0.63
40%	146,855	25,128,339	171.11	0.84
50%	163,817	30,425,479	185.73	1.01
Intronic segments
10%	115,258	10,958,920	95.08	0.37
20%	259,554	27,766,537	106.98	0.93
30%	459,821	52,189,014	113.50	1.74
40%	810,279	89,257,780	110.16	2.98
50%	1,403,977	146,631,328	104.44	4.89
Intergenic segments
10%	52,634	4,898,882	93.07	0.16
20%	119,843	12,621,975	105.32	0.42
30%	213,910	23,989,791	112.15	0.80
40%	375,395	41,208,385	109.77	1.37
50%	641,700	67,363,648	104.98	2.25
All Segments
10%	210,923	19,668,499	93.25	0.66
20%	479,947	51,415,935	107.13	1.71
30%	805,671	94,934,284	117.83	3.16
40%	1,332,529	155,594,504	116.77	5.19
50%	2,209,494	244,420,455	110.62	8.15

Characterization of Evolutionary Rates and Constraints in Three Mammalian Genomes