CHROMOSOME PROFILE OF LEISHMANIA-DONOVANI - INTERSTRAIN AND INTERSPECIFIC VARIATIONS

The genome of Leishmania donovani AG83, a virulent strain causing kala -azar, was resolved into 29 chromosomal bands by pulsed field gel elec trophoresis (PFGE) under standardized conditions. Comparison of the ka ryotype with those of other strains and species revealed variations. B y Southern hybridization, specific genes were localized to individual chromosomes. Twenty-two copies of beta-tubulin genes are located on ba nd 27 (1.63 Mb); minor copies are present in band 16 (850 kb) and band 9 (650 kb). A beta-tubulin related nontranscribed locus was isolated from a genomic library and shown to contain repetitive sequences hybri dizing throughout the genome. Single chromosomes contain multicopy clu sters of gp63 and mini-exon-derived RNA genes, but interspecific varia tions were observed in each case. The results emphasize the importance of using a standard reference strain of Leishmania donovani for coord inated genome mapping of this clinically important organism.