finnlakeviridae finnlakeviridae finnlakeviridae is a family of bacterial viruses that is not assigned to any higher taxonomic ranks. the family contains a single genus, finnlakevirus, which contains a single species, flavobacterium virus flip. this virus was isolated in 2010, with its gram-negative host bacterium, from lake jyväsjärvi, a boreal freshwater habitat in central finland, and is the first described single-stranded dna virus with an internal membrane. genome organization of flavobacterium phage flip. finnlakeviridae virus classification (unranked): virus realm: incertae sedis kingdom: incertae sedis phylum: incertae sedis class: incertae sedis order: incertae sedis family: finnlakeviridae subtaxa genus: finnlakevirus species: flavobacterium virus flip cryo-electron microscopic reconstruction of the flavobacterium phage flip virion the genome is circular single-stranded dna of about 9200 nucleotides in length.