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The evolution of cytoplasmic incompatibility types: integrating segregation, inbreeding and outbreeding

Jan Engelstädter1, Sylvain Charlat, Andrew Pomiankowski

  • 1Department of Biology, University College, The Galton Laboratories, London NW1 2HE, United Kingdom. j.engelstaedter@ucl.ac.uk

Genetics
|December 20, 2005
PubMed

Insights

Cytoplasmic incompatibility (CI) arises from maternally inherited bacteria. Evolution of new CI types is hindered by inbreeding but facilitated by outbreeding, impacting bacterial strain coexistence.

Area of Science:

  • Evolutionary biology
  • Microbial genetics

Background:

  • Cytoplasmic incompatibility (CI) is a reproductive barrier caused by maternally inherited bacteria like Wolbachia and Cardinium.
  • CI typically manifests as reduced offspring viability in crosses between infected males and uninfected females.
  • Incompatibility also occurs between individuals carrying different bacterial strains, complicating CI evolution.

Purpose of the Study:

  • To model the evolutionary processes driving the emergence of new cytoplasmic incompatibility (CI) types.
  • To investigate the impact of bacterial strain segregation and diverse breeding systems on CI evolution.

Main Methods:

  • Development of a theoretical model incorporating bacterial strain segregation during maternal transmission.
  • Analysis of a spectrum of breeding systems, from inbreeding to outbreeding.

Main Results:

  • Bacterial strain segregation makes the co-evolution of new CI types with pre-existing ones unlikely.
  • Inbreeding significantly impedes the evolution of novel CI types.
  • Outbreeding substantially facilitates the emergence of new CI types.

Conclusions:

  • The study provides insights into the evolutionary pathways of cytoplasmic incompatibility.
  • Outbreeding systems are more conducive to the diversification of CI.
  • The model offers a hypothesis for the evolutionary origins of CI.

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