FIGURE 1. Phylogram of the 12 sequenced species of Drosophila.

Phylogram derived using pairwise genomic mutation distances and the neighbour-joining method^{152, 153}. Numbers below nodes indicate the per cent of genes supporting a given relationship, based on evolutionary distances estimated from fourfold-degenerate sites (left of solidus) and second codon positions (right of solidus). Coloured blocks indicate support from bayesian (posterior probability (PP), upper blocks) and maximum parsimony (MP; bootstrap values, lower blocks) analyses of data partitioned by chromosome arm. Branch lengths indicate the number of mutations per site (at fourfold-degenerate sites) using the ordinary least squares method. See ref. 154 for a discussion of the uncertainties in the D. yakuba/D. erecta clade.