Figure 1.

Evolutionary distribution of putative dUT genes in double-stranded DNA viruses and single-stranded RNA viruses that replicate through a DNA intermediate (Ortervirales). The DNA viruses are proposed to have evolved from two distinct groups of bacteriophages (Tectiviridae and Caudovirales) [15]. The dotted line with a question mark indicates an unknown evolutionary relationship. Red indicates that no members have been reported to possess putative dUT gene, green indicates that at least one member has been reported to contain a dUT gene encoding a homotrimeric protein, while blue indicates that a least one member contains a dUT gene encoding a monomeric protein.