The extent of the centromeric tandem repeats on T. brucei chromosome 7. Analysis was carried out as described for Figures 1 and 2 using probes Tb24 and Tb15 (Additional file 1). Probe Tb24 was derived from a unique intergenic sequence. Fragment sizes derived in this study are indicated on the schematic, with the values from GeneDB in parentheses. The data suggest that the repeat arrays vary in length between chromosome homologues and stretch over at least100 kb (see also Table 1).