Table 3. The enrichment of the fragile sites in the repeatless duplication flanking sequences in different mammalian genomes.

Genome	Flanking, % (n)	Random, % (n)	Fold	P value
Human (hg16)	4.82 (2,052)	1.99 (2,964)	2.42	<10-7
Human (hg15)	3.81 (2,863)	2.41 (5,280)	1.58	<10-5
Mouse (mm3)	3.68 (815)	2.51 (2,632)	1.47	<0.05
Rat (rn3)	4.21 (570)	2.76 (1,123)	1.53	0.07

Listed are the percentages of the flanking and random regions containing fragile sites and the total number of sequences examined. Also shown are the folds of enrichment. The significance of the enrichment (P values) was computed by using two-sample t tests for binomial proportions.