Chromosome structure and sequence organization between pathogenic and non-pathogenic Leishmania spp

We have used a chromosome fragmentation strategy based on systematic genomi c insertions of the rare cutting yeast I-SceI endonuclease to assess struct ure and sequence organization of homologous chromosomes between evolutionar y divergent pathogenic and non-pathogenic Leishmania species. This method w as combined to physical mapping and hybridization studies using a number of specific chromosomal markers as probes. Our studies have concentrated on t wo different chromosomes of Leishmania major (L. major), L. donovani and L. infantum and of the non-pathogenic species L. tarentolae. Specific chromos ome fragmentation events at the level of multiple I-SceI genomic integratio ns indicated that very similar distances separated internal genomic sequenc es between homologous chromosomes and that distances from chromosome ends w ere more variable. The order and orientation of genes along the homologous chromosomes were also conserved between species. With only few exceptions, genome organization between pathogenic and non-pathogenic Leishmania specie s was found to be highly conserved. Genomic comparison of pathogenic and no n-pathogenic species may be useful for depicting regions involved in specie s-specific related pathologies. (C) 2000 Elsevier Science B.V. All rights r eserved.