Lifespan of restriction-modification systems critically affects avoidance of their recognition sites in host genomes

Table 2 Percentage of underrepresented sites of different types in the different datasets

R-M system site type	Actual pairs dataset	Experimentally proven dataset	Prokaryotic control dataset	Viral control dataset
Type I	0.0 %	0.0 %	0.1 %	0.1 %
Type I	0/100	0/14	238/357501	21/18859
Type III	0.0 %	0.0 %	0.3 %	0.2 %
Type III	0/76	0/7	213/82065	57/31571
Type IIC/G	0.0 %	0.0 %	0.1 %	0.2 %
Type IIC/G	0/107	0/47	171/218322	66/27699
Type II orthodox	47.9 %	45.3 %	3.9 %	1.7 %
Type II orthodox	850/1774	58/128	21380/542911	2720/158921
Type IIM	70.4 %	14.3 %	0.6 %	0.3 %
Type IIM	38/54^a	1/7	125/21128	79/29070
Type IV	0.0 %	0.0 %	1.0 %	0.2 %
Type IV	0/13	0/3	64/6342	25/10116

ISSN: 1471-2164