Figure 1. Relationships among tail needle C-terminal domains of the P22-like phages.

A neighbor-joining tree (created with Clustal X2 [80]) is shown with selected branch lengths (numbers between 0. and 1) and bootstrap values out of 1000 trials (between 1 and 1000). The nodes far from the branch tips are not well-supported and are not shown. A scale in fractional difference is shown in the lower left. Branches A, B and C have many members and the splits at these branch tips show the regions within which the individual members diverge (the larger tree in figure S1 shows the placement of all the individual sequences). The “phage Sf6” branch is not related to the other branches and its inclusion here is to demonstrate this, and does not imply any phylogenetic relationship with the other branches. The branches not labeled “phage” are from P22-like prophages in the following bacterial genome sequences: Rett1, Providencia rettgeri DSM 1131; Ars1, Arsenophonus nasoniae; APSE-1/−2, Hamiltonella defensa; øSG1, Sodalis glossinidius; Cart1, Pectobacterium carotovorum PBR1692; Morg1, Morganella morganii KT; Serr1/2/3, Serratia plymuthica strains AS9, AS12 and AS13; Blatt1/2, Escherichia blattae strains DSM 4481 and 105725.