Table 2. DNA homology within groups of phages, according to their virulent or temperate status.

Host	Phages	Group	Phage way of life	Length of genome homology between pairs of phages within a group (%)a
L.lactis	bIL285, bIL286, bIL309, r1t, Tuc2009	P335	temperate/lytic	10–33
	bIL310, bIL311, bIL312		temperate	7–10
	bIL67, c2	c6A	virulent	90
	bIL170, sk1	936	virulent	92
S.thermophilus	7201, DT1, O1205, Sfi11, Sfi19, Sfi21		temperate/lytic	27–93
B.subtilis	B103, phi-29, PZA		virulent	86–100
Mycobacterium	D29, L5		temperate/lytic	86
E.coli	T3, T7		virulent	82
	933W, H-19B, HK022, HK97, λ, N15, P22, VT2-Sa	lambdoid	temperate	0–91
	186, P2		temperate	59

^aPairs of phage within the group were compared using BLAST 2 sequences (14), and homology was expressed by the ratio (length of homology × 100)/total length of the shorter genome.

Accession numbers are as follows: 186, U32222; 7201, AF145054; 933W, AF125520; B103, X99260; bIL67, L33769; bIL170, AF009630; bIL285, bIL286, bIL309, bIL310, bIL311 and bIL312, this paper; c2, L48605; D29, AF022214; DT1, AF085222; H-19B, AF034975; HK022, AF069308; HK97, AF069529; L5, Z18946; λ, J02459; N15, AF064539; O1205, U88974; P2, AF063097; P22, AF217253; phi-29, M14430, V01155, M14782; PZA, M11813; r1t, U38906; Sfi11, AF158600; Sfi19, AF115102; Sfi21, AF115103; sk1, AF011378; T3, X17255; T7, V01146; Tuc2009 (G.Fitzgerald and D.van Sinderen, personal communication); VT2-Sa, AP000363.