Incipient evolution of Wolbachia compatibility types

Evolution. 2004 Sep;58(9):1901-8. doi: 10.1111/j.0014-3820.2004.tb00478.x.


Cytoplasmic incompatibility (CI) is induced in arthropods by the maternally inherited bacterium Wolbachia. When infected males mate with uninfected females or with females bearing a different Wolbachia variant, paternal chromosomes behave abnormally and embryos die. This pattern can be interpreted as resulting from two bacterial effects: One (usually termed mod, for modification) would affect sperm and induce embryo death, unless Wolbachia is also present in the egg, which implies the existence of a second effect, usually termed resc, for rescue. The fact that CI can occur in crosses between males and females infected by different Wolbachia shows that mod and resc interact in a specific manner. In other words, different compatibility types, or mod/resc pairs seem to have diverged from one (or a few) common ancestor(s). We are interested in the process allowing the evolution of mod/resc pairs. Here this question is addressed experimentally after cytoplasmic injection into a single host species (Drosophila simulans) by investigating compatibility relationships between closely related Wolbachia variants naturally evolving in different dipteran hosts: D. simulans, Drosophila melanogaster, and Rhagoletis cerasi. Our results suggest that closely related bacteria can be totally or partially incompatible. The compatibility relationships observed can be explained using a formal description of the mod and resc functions, implying both qualitative and quantitative variations.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biological Evolution*
  • Crosses, Genetic
  • Cytoplasm / microbiology
  • Cytoplasm / physiology
  • Drosophila / microbiology*
  • Drosophila / physiology
  • Host-Parasite Interactions
  • Models, Biological*
  • Reproduction / genetics
  • Reproduction / physiology
  • Species Specificity
  • Statistics, Nonparametric
  • Tephritidae / microbiology*
  • Tephritidae / physiology
  • Wolbachia / genetics*
  • Wolbachia / physiology