Smacoviridae: a new family of animal?associated single?stranded DNAviruses

AbstractSmacoviruses have small (?2.3-2.9 kb), circular single-stranded DNA genomes encoding rolling circle replication-associatedproteins (Rep) and unique capsid proteins. Although smacoviruses are prevalent in faecal matter of various vertebrates,including humans, none of these viruses have been cultured thus far. Smacoviruses display ?45% genome-wide sequencediversity, which is very similar to that found within other families of circular Rep-encoding single-stranded (CRESS) DNAviruses, including members of the families Geminiviridae (46% diversity) and Genomoviridae (47% diversity). Here, weannounce the creation of a new family Smacoviridae and describe a sequence-based taxonomic framework which was used toclassify 83 smacovirus genomes into 43 species within six new genera, Bovismacovirus (n=3), Cosmacovirus (n=1), Dragsmacovirus(n=1), Drosmacovirus (n=3), Huchismacovirus (n=7), and Porprismacovirus (n=28). As in the case of genomoviruses,the species demarcation is based on the genome-wide pairwise identity, whereas genera are established based on theRep amino acid sequence identity coupled with strong phylogenetic support. A similar sequence-based taxonomic frameworkshould guide the classification of an astonishing diversity of other uncultured and currently unclassified CRESS DNA virusesdiscovered by metagenomic approaches