Median-joining network of Rattus norvegicus cytochrome b (cyt b ) haplotypes based on full-length gene sequences. The circle size of south African Rattus haplotypes is proportional to the frequency of the haplotype. Haplotype colour coding is consistent with that used in Figure 1, viz. Yellow = south Africa (This study), Blue = Outside Africa (This study), Grey = Outside Africa (Genbank), Purple = Laboratory strains (Genbank). Each of the mutational steps separating haplotypes is indicated in blue and corresponds to the relevant position in the cyt b gene, whilst black nodes correspond to median vectors. Haplotype numbers are the same as those provided in Table 1.