Figure 1. Phylogenetic tree containing genus α-, β-, and γ-papillomaviruses.

The outer circle encompasses genera, the inner circle the species, and the numbers at the ends of the branches identify type. C-numbers refer to candidate HPV types. The four numbers associated with the arrows show the total number of HPV-positive DNA samples detected in lesion, perilesion, sun-exposed and sun-protected tissues, respectively. (These numbers take into account multiple infections with the same species in a given subject and, therefore, may differ from those listed in Table 2.) (Figure is modified from a previously published version by De Villiers et al. (2004), with copyright permission granted by Elsevier.)