The molecular karyotypes of several Leishmania isolates (Leishmania amazonensis, Leishmania
braziliensis, Leishmania guyanensis, Leishmania panamensis, Leishmania donovani, Leishmania
major, Leishmania aethiopica, Leishmania tropica, Leishmania enriettii) have been
analyzed by clamped homogeneous electric field (CHEF) gel electrophoresis. The chromosomal
localization of genes encoding 2 major surface glycoproteins, gp63 and gp46/M2, heat
shock protein 70 (hsp70), and beta-tubulin was determined for cloned isolates of 8
of these Leishmania species. The chromosome size class assignment of hsp70 genes was
most conserved in that all species contained a single hybridizing DNA band of approximately
1200 kb. The beta-tubulin gene probe hybridized predominantly to large (1600-1750
kb) chromosome-size DNA and to 1-5 additional bands, the number of which depended
on the species. The number and size of DNA bands hybridizing to gp63 or gp46/M2 gene
probes were not uniformly conserved among species. In contrast to previous reports
of gp63 genes being located on a single chromosome, using various CHEF gel conditions
we observed a Leishmania major gp63 gene probe hybridizing to at least 2 chromosomal
DNA bands in the New World species and in L. tropica. Gp46/M2 genes were located on
1 band in L. donovani, L. major, and L. aethiopica or 2 bands in L. tropica and L.
amazonensis, but surprisingly, do not hybridize to any chromosomal DNA of species
in the L. braziliensis complex or in L. enriettii. Whenever both genes were present
in a species, gp63 and gp46/M2 genes were located on different chromosomal DNA bands.