All reverse transcription (RT) reactions were completed using RNA templates obtained from linearized plasmid pHAV/7 transcribed in vitro with SP6 polymerase, total cellular RNA (1 g) isolated from virus infected cells using the RNA AqueousKit (Ambion, Austin, TX), or viral genomic RNAs (equivalent to 5 x 10 6 infectious particles) isolated directly from clarified tissue culture supernatants using the Fig. (1) . Dendrogram showing the grouping of HAV strains based on their genetic relatedness for developing viral probe sequences to be used for oligonucleotide design. HAV strains are identified by their GenBank accession number and their respective complete sequences were used to generate the dendrogram. Brackets encompass strain sequences selected to derive a group consensus sequence while arrows identify group individual (i.e. non-consensus) strain sequences for probe set development. Group sequences are designated by numbers 1-5 followed by the probe set identifier (within parentheses), and the genotype (I or II) and subgenotype (a or b) designation.