Genetic typing and phylogeny of the Leishmania donovani complex by restriction analysis of PCR amplified gp63 intergenic regions

Protozoan parasites of the Leishmania donovani complex (L. donovani, L. inf antum/L. chagasi) are causative agents of visceral leishmaniasis. To unders tand phylogeny and taxonomy within this group better we have developed 2 ne w polymerase chain reaction-linked restriction fragment length polymorphism (PCR-RFLP) analyses of the major surface protease (msp or gp63) intergenic (ITG) regions. We have named this approach map intergenic region RFLP typi ng (MIRT). One intergenic region lies between the constitutive map (mspC) a nd stationary phase msp (mspS4) genes (ITG/CS) and the other between multic opy logarithmic phase msp (mspL) genes (ITG/L). The markers generated robus t and congruent phylogenies, identifying 5 genetic clusters within L. donov ani. One cluster was synonymous with L. infantum (L. chagasi); clusters str ongly correlated with isoenzyme typing and some with geographical origin. T hese genetic groups map be important for epidemiological and clinical studi es. The congruence of the groups identified indicates suitability of these genomic targets for taxonomic studies. Furthermore, subgroups of L. donovan i were of equivalent phylogenetic status to L. infantum. No evidence was fo und to support the existence of L. archibaldi. It is likely to be necessary in future to re-evaluate the taxonomic status of L. donovani or of L. infa ntum, as discrete species.