Genetic diversity and population structure of Phlebotomus orientalis (Diptera: Psychodidae) from selected regions in Sudan

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Mona Siddig Mohammed, Numairy
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In Sudan, Phlebotomus orientalis is the principal vector of Leishmania donovani in the active foci of visceral leishmaniasis in eastern and southern Sudan. Therefore, the present study was carried out to investigate the genetic diversity of five natural populations of P. orientalis based on polymorphism analysis of RAPD-PCR loci. Phlebotomus orientalis were collected during 2006-2007 from Dinder National Park (DNP), Rahad River area (RH), Atbara River area (ATB), White Nile area (WN) and Surogia village (SR). The genomic DNA was extracted from each individual fly and then the DNA specimens were identified using specific primers. Also, females of P. orientalis from the five geographic regions were screened using RAPD-PCR. In this study, eleven sandfly species were recorded. All samples amplified using diagnostic-PCR were found to contain a band size 675 bp which specific for P. orientalis. Of 30 RAPD primers used in this study only four produced different banding pattern within and among the populations of different regions. Two common bands at 300 bp in all populations of P. orientalis were produced by two different RAPD primers. Population of DNP showed the highest number of genotypes (62) whereas WN population showed the lowest number (9). In contrast, the WN population produced the highest number of fragments (717) whereas ATB population produced the lowest number (112). The population of each site showed characteristic diagnostic bands by all RAPD primers; the exception was the population of RH. Moreover, populations P. orientalis showed different level of diversity at the RAPD loci (P% = 93%-41%; HE =0.1.3-0. 17). Moreover, Dice coefficient showed high similarities between the populations of DNP, RH and SR whereas, the populations of WN and ATB showed low similarities to the other populations. Hieratical clustering method for P. orientalis populations obtained by each RAPD primer and all RAPD primers showed clear clustering of these populations based on their geographic origin. Results obtained by Mantel test showed that no correlation between the genetic of the Populations and the geographic distance of collection sites in Sudan. The results obtained by AMOVA test on the genetic structure of P. orientalis showed a high proportion of variation between individuals of P. orientalis (95.7%) and moderate proportion of variation among groups with populations (4.3%) and among populations (1.6%). The fixation index (FST) estimated by AMOVA test showed low genetic difference between the population of P. orientalis. Further work is needed to sequence the diagnostic DNA fragments of each P. orientalis populations obtained in this study which will give more information on the magnitude of the genetic variation among these populations.
Genetic diversity and population structure of Phlebotomus orientalis (Diptera: Psychodidae) from selected regions in Sudan