Independent phylogenetic trees (online Technical Appendix 2) and similarity matrices were constructed for the 3 genomic regions. Since the last common ancestor and as depicted on the distance matrices and highlighted by boxplots of maximum-likelihood branch length distributions (online Technical Appendix 2 Figure 3 ), there are more mutations fi xed in the VP1 region than in the 3CD region, and more in the 3CD region than in 5′-UTR, which is indicative of a variable rate of evolution in these regions. Accordingly, VP1 sequences enabled genotyping of all but 3 clinical strains analyzed (online Technical Appendix 2, Figure 1 , panel B). These strains may represent rhinovirus genotypes only distantly related to predefi ned reference serotypes. In contrast, genotyping based on 3CD and 5′-UTR was less accurate, as expected. These results confi rmed that molecular typing of rhinoviruses, similarly to other picornaviruses, must use capsid sequences.