Phycodnaviridae

Baltimore Classification

Higher order taxa

Viruses; dsDNA viruses, no RNA stage; Phycodnaviridae

Genera

Chlororvirus, Coccolithovirus, Phaeovirus, Prasinovirus, Prymnesiovirus

Description and Significance

Phycodnaviridae are viruses with double-stranded DNA that infect chlorella, algal symbionts of paramecia and hydras.

Genome Structure

The genome of phycodnaviridae is not segmented and contains a single molecule of linear double-stranded DNA. The complete genome is 250000-350000 nucleotides long. The genome guanine+cytosine content is 40-52 %. The genome contains unusual bases, varying from 0.1-47 %. These bases are 5-methyl deoxy-cytosine residues and N6-methyl deoxy-adenosine residues in some DNAs. The double-stranded DNA is non-permuted and the genome sequence has termini with cross-linked hairpin ends. The genome, except for the hairpin, has terminally redundant sequences. These sequences have inverted terminal repetitions (ITR) for at least 2000 bases. (source: ICTVdB Descriptions)