This virus has a circular single stranded RNA genome of about 1700 nucleotides. It has a ribozyme (RNA cleavage) activity. This is the smallest known genome for an animal virus.
RNA and delta antigen (195 AA) are packaged in a Hepatitis B particle. No DNA intermediate has been detected during the replication phase and it is thought that replication occurs by RNA directed RNA synthesis using a DNA dependent RNA polymerase. Certain parts of the genome and the pattern of replication is of course similar to a viroid. One difference is that mRNA and a protein - the delta antigen - are made.