Fig. 7.

Retroviral envelopes with high similarity between Env subgroups. Envelope subgroups (A, B, C, etc) with high intersupergroup similarity are shown interconnected, superimposed on the cladogram of Fig. 3. Significant relations (branches with bootstrap >50) were obtained from neighbour joining (not shown) and maximum likelihood trees (same as in Fig. 6). To avoid cluttering, only intersupergroup relations were shown, except for the HML supergroup, where intergroup relations are presented. Relations shown indicate, but do not prove, an envelope transfer event