Fig. 1.

(A) The genome organization of small RNA phages ϕCb5, MS2, Qβ, and AP205. Genes are drawn to their approximate scale. (B) Unweighted-pair group method using average linkages (UPGMA) tree of small RNA phages, based on sequence alignment of the RP central part and structure-based alignment of CP. AP205 is not included in the CP alignment-based tree, since its structure is unknown and the CP sequence itself shows no significant similarity to other phages. Trees were constructed by MEGA (17).