Genetic diversity and population structure of Glossina pallidipes in Uganda and western Kenya

Abstract

BackgroundGlossina pallidipes has been implicated in the spread of sleeping sickness from southeastern Uganda into Kenya. Recent studies indicated resurgence of G. pallidipes in Lambwe Valley and southeastern Uganda after what were deemed to be effective control efforts. It is unknown whether the G. pallidipes belt in southeastern Uganda extends into western Kenya. We investigated the genetic diversity and population structure of G. pallidipes in Uganda and western Kenya.ResultsAMOVA indicated that differences among sampling sites explained a significant proportion of the genetic variation. Principal component analysis and Bayesian assignment of microsatellite genotypes identified three distinct clusters: western Uganda, southeastern Uganda/Lambwe Valley, and Nguruman in central-southern Kenya. Analyses of mtDNA confirmed the results of microsatellite analysis, except in western Uganda, where Kabunkanga and Murchison Falls populations exhibited haplotypes that differed despite homogeneous microsatellite signatures. To better understand possible causes of the contrast between mitochondrial and nuclear markers we tested for sex-biased dispersal. Mean pairwise relatedness was significantly higher in females than in males within populations, while mean genetic distance was lower and relatedness higher in males than females in between-population comparisons. Two populations sampled on the Kenya/Uganda border, exhibited the lowest levels of genetic diversity. Microsatellite alleles and mtDNA haplotypes in these two populations were a subset of those found in neighboring Lambwe Valley, suggesting that Lambwe was the source population for flies in southeastern Uganda. The relatively high genetic diversity of G. pallidipes in Lambwe Valley suggest large relict populations remained even after repeated control efforts.ConclusionOur research demonstrated that G. pallidipes populations in Kenya and Uganda do not form a contiguous tsetse belt. While Lambwe Valley appears to be a source population for flies colonizing southeastern Uganda, this dispersal does not extend to western Uganda. The complicated phylogeography of G. pallidipes warrants further efforts to distinguish the role of historical and modern gene flow and possible sex-biased dispersal in structuring populations.

Detecting Wahlund effects together with amplification problems: Cryptic species, null alleles and short allele dominance in Glossina pallidipes populations from Tanzania

“…In clade A, for which we disposed of a reasonable sample size, isolation by distance slope and effective population size analyses suggested relatively small densities but quite large dispersal distances (2–8 km per generations on average and up to 14 km), which is not so different to what mark‐release recapture suggests for this species (Ouma, Marquez, & Krafsur, ). Isolation by distance was never accurately explored in the literature for this species, either because it was not really studied (Ouma et al, ; Ouma, Marquez, & Krafsur, ) or because it was analyzed with temporally heterogeneous subsamples (Okeyo et al, ). Clade B contained few and very small subsamples and the differences observed with Clade A might not be significant.…”

Implications of Microfauna-Host Interactions for Trypanosome Transmission Dynamics in Glossina fuscipes fuscipes in Uganda

“…As a result, neighboring populations can vary in Wolbachia prevalence. Male-biased dispersal has been observed in G. pallidipes (50) and in G. fuscipes fuscipes (37). Furthermore, females are known to have multiple matings (10).…”

Analysis of Multiple Tsetse Fly Populations in Uganda Reveals Limited Diversity and Species-Specific Gut Microbiota

“…The species in the palpalis group also have strong human host preferences, while the species in the morsitans complex typically have broader host specificity (63). Given that genetic data from Uganda suggest that tsetse individuals do not move for long distances (64,65), we assumed that flies captured in the same locations were likely to have been exposed to similar microenvironments. Thus, we reasoned that microbiota composition differences observed in individuals of the different species in MF may arise from biotic differences associated with blood-feeding preferences or genetic differences.…”