Wolbachia association with the tsetse fly, Glossina fuscipes fuscipes, reveals high levels of genetic diversity and complex evolutionary dynamics
Loading...
Date
2013
Journal Title
Journal ISSN
Volume Title
Publisher
BMC evolutionary biology
Abstract
Wolbachia pipientis, a diverse group of α-proteobacteria, can alter arthropod host reproduction and
confer a reproductive advantage to Wolbachia-infected females (cytoplasmic incompatibility (CI)). This advantage
can alter host population genetics because Wolbachia-infected females produce more offspring with their own
mitochondrial DNA (mtDNA) haplotypes than uninfected females. Thus, these host haplotypes become common or
fixed (selective sweep). Although simulations suggest that for a CI-mediated sweep to occur, there must be a
transient phase with repeated initial infections of multiple individual hosts by different Wolbachia strains, this has
not been observed empirically. Wolbachia has been found in the tsetse fly, Glossina fuscipes fuscipes, but it is not
limited to a single host haplotype, suggesting that CI did not impact its population structure. However, host
population genetic differentiation could have been generated if multiple Wolbachia strains interacted in some
populations. Here, we investigated Wolbachia genetic variation in G. f. fuscipes populations of known host genetic
composition in Uganda. We tested for the presence of multiple Wolbachia strains using Multi-Locus Sequence
Typing (MLST) and for an association between geographic region and host mtDNA haplotype using Wolbachia
DNA sequence from a variable locus, groEL (heat shock protein 60).
Results: MLST demonstrated that some G. f. fuscipes carry Wolbachia strains from two lineages. GroEL revealed high
levels of sequence diversity within and between individuals (Haplotype diversity = 0.945). We found Wolbachia
associated with 26 host mtDNA haplotypes, an unprecedented result. We observed a geographical association of
one Wolbachia lineage with southern host mtDNA haplotypes, but it was non-significant (p = 0.16). Though most
Wolbachia-infected host haplotypes were those found in the contact region between host mtDNA groups, this
association was non-significant (p = 0.17).
Conclusions: High Wolbachia sequence diversity and the association of Wolbachia with multiple host haplotypes
suggest that different Wolbachia strains infected G. f. fuscipes multiple times independently. We suggest that these
observations reflect a transient phase in Wolbachia evolution that is influenced by the long gestation and low
reproductive output of tsetse. Although G. f. fuscipes is superinfected with Wolbachia, our data does not support
that bidirectional CI has influenced host genetic diversity in Uganda.
Description
Keywords
Wolbachia, Population structure, Sequence diversity, GroEL, MLST
Citation
Symula et al.: Wolbachia association with the tsetse fly, Glossina fuscipes fuscipes, reveals high levels of genetic diversity and complex evolutionary dynamics. BMC Evolutionary Biology 2013 13:31. doi:10.1186/1471-2148-13-31