Maximum likelihood phylogenetic trees show that BES promoter and ESAG6 sequences from T. b. gambiense 972 (Tbg) cluster separately from those from T. b. brucei EATRO 2340 (Tbb) and T. equiperdum STIB 818 (Teq). The DNA sequence types are as listed in Tables 1-3. Sequence accession numbers are listed in the Materials and Methods. Alignments of the BES promoter sequences used are shown in the supplementary material (Additional file 2). Bootstrap support values are shown for key nodes only.