Phylogenetic relationships of linear, protein-primed replicating genomes

Relative phylogenetic distances were estimated for those linear plasmids for which sequencing data were available by comparing the amino-acid sequences of the putative DNA- and RNA-polymerases, and phylogenetic trees were calculated. The relationships obtained accord well with those indicated by other structural characteristics of these genetic elements. It is obvious that linear plasmids constitute a separate group of genetic traits when compared with those of the adenoviruses. However, an overall relationship to these viruses is evident. Among the linear plasmids at least two main groups can be recognized, namely the cytoplasmically and the mitochondrially localized elements.