GENES AND CHROMOSOMES OF LEISHMANIA-INFANTUM

During recent years, sever-al Leishmania infantum genes have been clon ed and characterized Here, we have summarized the available informatio n on the gene organization and expression in this protozoan parasite. Fr om a comparative analysis, the following outstanding features were found to be common to most of the genes characterized: tandemly organi zed genes with conserved coding regions and divergent untranslated reg ions, polycistronic transcription and post-transcriptional regulation of gene expression. The analysis of chromosomes of L. infantum by puls ed-field electrophoresis showed the existence of both size and number polymorphisms such that each strain has a distinctive molecular karyot ype. Despite this variability, highly conserved physical linkage group s exists among different strains of L. infantum and even among Old Wor ld Leishmania species. Gene mapping on the L. infantum molecular karyo type evidenced a bias in chromosomal distribution of at least, the evo lutionary conserved genes.