Table 4.

Strain-specific H. pylori genes present exclusively in strain 98-10 or B128

	Number of genes in the indicated strain(s)a
	98-10	B128	98-10 and B128
Total number of strain-specific genesa	22	51	16
Functional class
Transposase	2	3	6
Type IV secretion gene clusterb	0	7	0
Hypothetical	17	37	9
No database match	8	8	2
Closest match lacks known function	9	29	7
Other	3	4	1
Gene islands containing strain-specific genesc	2	11	3

^aPresent in the indicated strain(s), but not in any of the other four strains for which genome sequences are available.

^bThis group of genes was not detected in the original analysis of the genome from strain J99, but was subsequently detected in strain J99 [43].

^cFor this analysis, an island was considered to be present if two or more strain-specific genes were in contiguous chromosomal loci.