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.

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hdl.handle.net/1765/2959
Biochimica et Biophysica Acta - General Subjects
Erasmus MC: University Medical Center Rotterdam

Borst, P., Fase-Fowler, F., Hoeijmakers, J., & Frasch, A. C. C. (1980). Variations in maxi-circle and mini-circle sequences in kinetoplast DNAs from different Trypanosoma brucei strains. Biochimica et Biophysica Acta - General Subjects, 610, 197–210. Retrieved from http://hdl.handle.net/1765/2959