Signatures of Domain Shuffling in the Human Genome

Table 5.

Observed and Expected Numbers of Symmetrical Class 2 Domains in the Human Genome

Category	Comb.	Obs.	Exp.	P
2 exon domains
Domain (367)	0–0	31	16.1	<0.02
	1–1	194	156.9	<10⁻⁴
	2–2	10	7.4	0.33
	$\text{[math]}$	235	180.4	<10⁻⁷
Domain family (74)	0–0	10.6	8.6	0.47
	1–1	21.5	14.6	<0.05
	2–2	2.8	3.4	n.d.
	$\text{[math]}$	34.9	26.6	<0.05
3 exon domains
Domain (155)	0–0	23	18.1	0.22
	1–1	50	38.5	<0.05
	2–2	6	3.8	n.d.
	$\text{[math]}$	79	60.4	<0.01
Domain family (63)	0–0	12.7	11.7	0.75
	1–1	12.3	8.3	0.14
	2–2	3.5	2.6	n.d.
	$\text{[math]}$	28.5	22.5	0.12
4 exon domains
Domain (115)	0–0	24	18.9	0.2
	1–1	33	20.9	<10⁻³
	2–2	3	3	n.d.
	$\text{[math]}$	60	42.8	<10⁻³
Domain family (49)	0–0	10.1	9.6	0.86
	1–1	9.5	5.9	0.11
	2–2	1	0.6	n.d.
	$\text{[math]}$	20.6	16.1	0.17
5 exon domains
Domain (70)	0–0	25	22.8	0.57
	1–1	5	2.7	n.d.
	2–2	0	1.9	n.d.
	$\text{[math]}$	30	27.4	0.52
Domain family (39)	0–0	15	12.4	0.37
	1–1	3.5	1.9	n.d.
	2–2	0	1	n.d.
	$\text{[math]}$	18.5	14.3	0.16
6 exon domains
Domain (75)	0–0	27	22.8	0.29
	1–1	6	4.3	n.d.
	2–2	3	3.1	n.d.
	$\text{[math]}$	36	30.2	0.17
Domain family (43)	0–0	16.7	14.6	0.5
	1–1	2.7	2	n.d.
	2–2	2.3	1.6	n.d.
	$\text{[math]}$	21.7	18.2	0.28

↵Total numbers of domains and families in each category are indicated in parentheses. Summed symmetrical combinations are shown in boldface. The expected values were calculated based on the frequencies of flanking intron phases. (Comb.) Combinations; (Obs.) observed; (Exp.) expected.

This Article

Genome Res. 2002. 12: 1642-1650

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