Journal Name:
BMC Evolutionary Biology
Volume:
8
Issue:
1
Pages From:
183
To:
196
Date:
Tuesday, June 24, 2008
Abstract:
Background: Leishmania (Leishmania) major, one of the agents causing cutaneous leishmaniasis (CL) in
humans, is widely distributed in the Old World where different species of wild rodent and phlebotomine
sand fly serve as animal reservoir hosts and vectors, respectively. Despite this, strains of L. (L.) major
isolated from many different sources over many years have proved to be relatively uniform. To investigate
the population structure of the species highly polymorphic microsatellite markers were employed for
greater discrimination among it's otherwise closely related strains, an approach applied successfully to
other species of Leishmania.
Results: Multilocus Microsatellite Typing (MLMT) based on 10 different microsatellite markers was
applied to 106 strains of L. (L.) major from different regions where it is endemic. On applying a Bayesian
model-based approach, three main populations were identified, corresponding to three separate
geographical regions: Central Asia (CA); the Middle East (ME); and Africa (AF). This was congruent with
phylogenetic reconstructions based on genetic distances. Re-analysis separated each of the populations
into two sub-populations. The two African sub-populations did not correlate well with strains'
geographical origin. Strains falling into the sub-populations CA and ME did mostly group according to their
place of isolation although some anomalies were seen, probably, owing to human migration.
Conclusion: The model- and distance-based analyses of the microsatellite data exposed three main
populations of L. (L.) major, Central Asia, the Middle East and Africa, each of which separated into two subpopulations.
This probably correlates with the different species of rodent host.
