Evaluation of Genetic Diversity among Glossina Fuscipes subpopulations from sleeping sickness foci in Uganda using Microsa Tellite DNA markers

Abstract

Vector population genetic structure is rarely analyzed yet it is important in the understanding of the epidemiology of vector borne diseases and their control. In this study, patterns of genetic variation in the tsetse fly Glossina fuscipes fuscipes, the main vector of Human African Trypanosomosis (HAT) and Animal African Trypanosomosis (AAT) were assessed at five microsatellite loci. A total of 286 individuals were sampled from seven putative subpopulations in Uganda. Six of the subpopulations (Lumino, Kwapa, Osukuru, Namungalwe, Kaliro, and Serere) are sleeping sickness foci where the disease is endemic and the numbers of cases sometimes escalate. In one subpopulation (Ogur), G. f. fuscipes exists but active transmission is rarely observed. The mean number of alleles per locus for each of the subpopulations was relatively moderate ranging from 2 to 7 with generally low gene diversity (HE ranging from 0.2455 to 0.4376). Analysis of population structure with 21 possible pair wise comparisons revealed 12 significantly divergent pairs of which, Kaliro and Lumino populations had the least divergence (FST =0.0443, P>0.05) while Kaliro and Serere represented the highest divergence (FST =0.2288, P<0.0000). Analysis of molecular variance (AMOVA) indicated significant differentiation at all hierarchical levels between populations (FST = 0.1474, P<0.001), among populations within each group (FSC = 0.0313, P<0.001) and between the two groups (FCT = 0.1199, P<0.001). These data show that G. f. fuscipes populations are highly structured, with clearly defined northern and southern cluster that are separated by Lake Kyoga. These results are interpreted in terms of their implications for an area-wide integrated tsetse and trypanosomosis control/elimination strategy.