Complete circular DNA genome of a TT virus variant (isolate name SANBAN) and 44 partial ORF2 sequences implicating a great degree of diversity beyondgenotypes

Information on the entire genome of TT Virus (TTV) has been scarce. The cir cular ssDNA genome of a variant (isolate name SANBAN) that we sequenced was only 56.7% homologous to the prototype isolate (TA278), with even lower ho mology at the amino acid level: 34.2% for ORF1 and 39.7% for ORF2. Regardin g the ORF1, SANBAN was only very distantly related to the six major TTV gen otypes reported to date. In partial ORF2 sequences determined on 44 isolate s taken together, TTV has a broad range of genetic diversity and the SANBAN isolate may represent a new TTV-like viral species or genus and not merely a genotype of TTV. (C) 1999 Academic Press.