Phylogenetic tree of gymnosperm and angiosperm R2R3-MYB proteins. This neighbour-joining (1000 Bootstraps) tree was based on the Clustal W alignment of the complete coding sequences of 13 spruce and five pine MYB proteins identified in this study (represented by filled and empty lozenges, respectively). The bar indicates an evolutionary distance of 0.2%. Arabidopsis proteins were chosen as landmarks representing the three main groups (circles A, B and C) and subgroups (Sg next to bracket; nd, not determined) defined by Romero et al.  and Kranz et al. . Human c-MYB [GenBank: P10242] and Mus musculus MmMYBA [GenBank: X82327] were not used as out groups but as landmarks. The accession numbers of the Arabidopsis genes are given in Methods. Other abbreviations are in Figure 1.