Contribution of each mutational category (transition and transversion) to the development of drug-resistant substitutions (variants) in the NS3 and NS5B proteins reported in this study.

The genetic barrier score (GBS) was calculated according to the model described by Van de Vijver et al.(50) A score of 1 is assigned to transitions (A↔G and C↔T) and 2.5 to transversions (A↔C, A↔T, G↔C and G↔T). Natural polymorphisms are indicated in italic. Numbers of isolates are indicated in parenthesis.