A POLYMORPHIC MINISATELLITE SEQUENCE IN THE SUBTELOMERIC REGIONS OF CHROMOSOME-I AND CHROMOSOME-V IN LEISHMANIA-INFANTUM

A minisatellite DNA sequence is described for the first time in Leishm ania infantum. It is borne by four chromosomes and consists of an 81-b p repeat unit organised in several clusters. On chromosomes I and V of L. infantum, the clusters are tightly located in the size-variable su btelomeric regions. The organisation of this sequence may be related t o that of the subtelomeric interspersed repeat sequences identified in the human genome. The sequencing of seven repeat units, some subclone d from the same cluster, allowed the definition of a consensus sequenc e of 81 bp, particularly G/C rich (73%), Two subfamilies were clearly defined: one exhibits a 91-95% homology with the consensus sequence; t he second one comprises two monomers sharing a 91% homology but only 7 7% homology with the consensus sequence. The two types of monomers can be found in the same cluster. These data suggest interactions between monomers and a possible role of this sequence in the instability of t hese regions. Finally, restriction fragment length polymorphisms were revealed by this sequence among various strains of L. infantum. Beside s allowing the detection of recombination events in the unstable regio ns of the chromosomes, this new marker may become a useful tool in the study of the parasite population dynamics in leishmaniasis foci.