Genetic heterogeneity in the Trypanosoma brucei gambiense genome analysed by random amplification of polymorphic DNA.

Abstract

The random amplification of polymorphic DNA (RAPD) technique has the potential to produce large amounts of characterisation data very quickly and simply, using far less DNA than conventional restriction-fragment-length polymorphism (RFLP) analysis. In the present study we assessed genetic heterogeneity among 34 Trypanosoma brucei gambiense isolates from various endemic areas in Africa by the RAPD technique using 8 arbitrary primers and compared the results with those obtained previously from RFLP analysis of polymorphisms in 5 variant surface glycoprotein (VSG) genes. The isolates were compared both among themselves and with 3 T. b. non-gambiense isolates. Most of the primers produced RAPD profiles specific for T. b. gambiense, with 4 primers showing marked polymorphisms between T. b. gambiense and non-gambiense stocks. These primers also showed minor variations between the T. b. gambiense stocks, and 2 revealed differences between Cameroonian stocks. These results were comparable with those produced by RFLP analysis, where certain polymorphisms are characteristic of T. b. gambiense. Numerical analysis showed a high correlation between the RAPD and RFLP data, with genetic variation being detected at a finer level by RAPD analysis. We conclude that RAPD analysis provides a simple and accurate method for the characterisation of T. b. gambiense.