CONSERVATION AMONG OLD-WORLD LEISHMANIA SPECIES OF 6 PHYSICAL LINKAGEGROUPS DEFINED IN LEISHMANIA-INFANTUM SMALL CHROMOSOMES

We have characterised 49 DNA probes specific for each of the six small est chromosomes in Leishmania infantum and have examined the allocatio n of these probes in the molecular karyotypes of the other Old World L eishmania species Leishmania donovani, Leishmania major, Leishmania tr opica and Leishmania aethiopica. These 49 probes define 6 physical lin kage groups in the molecular karyotypes of various strains of L. infan tum. 40 of these probes hybridise in the other Old World Leishmania sp ecies and show a remarkably conserved linkage pattern. No interchromos omal exchange nor fusion could be detected. Thus, in spite of the chro mosomal size polymorphisms, the general structure of the genome seems to be conserved in the six smallest chromosomes among Old World Leishm ania species. This structural genomic homogeneity should be helpful fo r mapping studies of any Old World Leishmania genomes.