title: Variations in maxi-circle and mini-circle sequences in kinetoplast DNAs from different Trypanosoma brucei strains.
abstract: We have compared a total of 30 recognition sites for eight restriction endonucleases on the 20-kilobase-pair maxi-circle of kinetoplast DNAs from five different Trypanosoma brucei strains. In addition to three polymorphic sites were have found a 5 kilobase-pair region that is not cleaved by any of the eight enzymes and that varies in size over 1 kilobase pair in the strains analysed. Mini-circles from these five strains, digested with endonuclease TaqI or MboII, yield very complex fragment patterns, showing that extensive mini-circle sequence heterogeneity is a common characteristic of these T. brucei strains. The size distribution of mini-circle fragments in these digests was identical for different clones of the 427 strain, but very different for mini-circles from different strains. These results show that maxi-circle sequence is conserved, whereas mini-circle sequence is not. Restriction digests of maxi-circles could be useful in determining how closely two Trypanosoma strains are related, whereas mini-circle digests can serve as sensitive tags for individual strains.
mesh_terms: D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D005075:Biological Evolution; D002874:Chromosome Mapping; D004262:DNA Restriction Enzymes; D004270:DNA, Circular / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics*; D008970:Molecular Weight; D013045:Species Specificity; D014346:Trypanosoma brucei brucei / Q000235:genetics*
chemical_list: D004270:DNA, Circular; D004272:DNA, Mitochondrial; D004262:DNA Restriction Enzymes