Assignment of genes to Leishmania infantum chromosomes: karyotype and ploidy

The use of various pulsed-field electrophoresis methodologies under different conditions allowed us to determine the Leishmania infantum karyotype. A total of 25 chromosomal bands ranging in size from 375 to 3300 kb were resolved amounting to a minimum genomic DNA mass of about 2.6 x 10(7) pb. By molecular hybridization and on the basis of the karyotype, specific gene sequences could be assigned to particular chromosomes. A bias in the chromosomal distribution of different markers was found since 9 out of the 12 analysed gene markers hybridize with chromosomal bands XIXa and XIXb. We infer that chromosomal bands XIXa and XIXb, differing in about 30 kb, could be representing a pair of homologous chromosomes and that another pair of homologs may be also defined by chromosomal bands XVII and XVIII.