Abstract:
In order to explore genomic plasticity at the level of the mini-exon gene-bearing chromosome in natural
populations of Leishmania, the molecular karyotype of 84 Leishmania stocks belonging to subgenus Viannia,
originating mostly from Peru and Bolivia, and di ering according to eco-geographical and clinical parameters, was
resolved and hybridised with a mini-exon probe. The results suggest that size variation of the mini-exon genebearing chromosome is frequent and important (up to 245-kb size-di erence), and partially involves variation (up to
50%) in copy number of mini-exon genes. There is no signi®cant size-di erence between mini-exon-bearing
chromosomes of Peruvian and Bolivian populations of cutaneous and mucosal isolates of Leishmania (Viannia)
braziliensis, but there is between eco-geographical populations of Leishmania (Viannia) peruviana. Leishmania (V.)
peruviana presented a signi®cantly smaller mini-exon-bearing chromosome than the other species of subgenus
Viannia. The contrast between the general chromosome size heterogeneity and the homogeneity observed in some
Peruvian Andean areas is discussed in terms of selective pressure. # 1999 Australian Society for Parasitology Inc.
Published by Elsevier Science Ltd. All rights reserved.
