POLYMORPHISMS IN TRYPANOSOMA-CRUZI - EVIDENCE OF GENETIC-RECOMBINATION

The ploidy of Trypanosoma cruzi is until now undetermined although ana lysis of isoenzymes, molecular karyotype and DNA content suggest diplo idy in a very plastic genome. Also, there has been no convincing demon stration of genetic exchange and it has been proposed that reproductio n is clonal. We have compared 18 T. cruzi stocks and clones from the s ame area or host by means of isoenzyme analysis (12 loci) and restrict ion site polymorphisms in and around three glycolytic genes (glycerald ehyde-3-phosphate dehydrogenase, aldolase and glucosephosphate isomera se). The analysis demonstrated the presence of homozygotes and heteroz ygotes and is compatible with diploidy for these housekeeeping genes. This strongly supports the hypothesis of genetic exchange in T. cruzi and further elucidates the genetic diversity within natural T. cruzi p opulations.