Genetic variability within the species Leishmania infantum by RAPD. A lack of correlation with zymodeme structure

The infraspecific variability of the species Leishmania infantum is studied by using genetic markers generated by random amplified polymorphic DNA (RAPD). We have applied this technique, using 18 primers of arbitrary sequence, to 33 strains of the parasite belonging to 18 zymodemes isolated in different clinical forms and hosts. Other strains belonging to the species L. donovani, L. major, L. tropica and L. mexicana were used as a reference. The RAPD technique produced very different genetic profiles between L. infantum and L. major, L. tropica and L. mexicana with all primers used, whereas 11 of the 18 primers distinguished L. infantum strains from the species L. donovani. All primers except 1 (TAF 300), generated polymorphism in the L. infantum strains. The dendrograms constructed with the isoenzyme data and with RAPD are congruent in relation to the separation of the different species but show little agreement within the L. infantum species, reflecting the genetic heterogeneity of the strains belonging to one zymodeme. A geographical structuralisation is observed with two diverging groups that evolve independently whereas there is no relation between the genotype of the parasite and the host or between the former and the clinical form of the disease.