Comparative genomic hybridization and sequence analysis comparing SVV BAC to WT SVV. A) Schematic representation of the SVV genome highlighting the SVV ORFs (arrows) that contain sequence changes. Sequence variation results in different hybridization intensities indicated by the hybridization ratio between SVV BAC and WT SVV and signal potential nucleotide changes. B and C) The regions containing sequence variations were amplified by PCR and directly sequenced. Sequencing identified: B) within ORF 22 a transition occurs from G to A resulting in a missense mutation, C) within ORF 62/71 a transition from T to C results in a silent mutation (note the nucleotide and position number refers to the genomic position). Nucleotide substitution (bold italics).