Microorganisms that are passed from one generation to the next through their hosts (i.e. heritable microorganisms) are widespread among animals. They are typically inherited through the cytoplasm of their hosts, but other mechanisms of transmission also exist. The kinds of microorganisms involved range from viruses to bacteria, fungi and protozoa. The interactions of heritable microorganisms with their hosts range from mutualistic (beneficial) to parasitic. There is growing evidence that heritable microorganisms are extremely important in evolution.
Over the years I have studied a variety of inherited bacteria, particularly those that alter host reproduction (i.e. reproductive parasites). Current research focuses on Wolbachia, an amazing group of intracellular rickettsia that have evolved as reproductive parasites of arthropods. Wolbachia cause a number of interesting effects upon their hosts, including reproductive incompatibility between host strains or species (called cytoplasmic incompatibility or CI), parthenogenesis, and feminization of genetic males. These bacteria are of particular interest because they may cause rapid speciation in their hosts, and they are also of potential value in biological control of pest insects.
Recent and Other Selected Publications(click here to get pdf files for some of the papers below )
Baldo, L., N. Lo, and J.H. Werren. The Mosaic Nature of the Wolbachia Surface Protein (wsp). J. Bacteriology (In Press).
Telschow, A., J.H. P. Hammerstein, and J.H. Werren. Wolbachia, reinforcement and speciation. Evolution (In Press).
Telschow, A., Yamamura, N. and J.H. Werren. Bidirectional CI, Cytoplasmic Divergence and the Stable Coexistence of Two Strains in Structured Host Populations. J. theor. Biol. (In Press).
Werren, J.H. 2005. Heritable microorganisms and reproductive parasitism. In. Microbial Evolution: Concepts and Controversies. J. Sapp (ed.) Oxford University Press (New York).
Keller, G.P., D.M. Windsor, J. Saucedo, and J.H. Werren. 2004. Reproductive effects and geographical distribution of two Wolbachia strains infecting the Neotropical beetle, Chelymorpha alternans (Chrysomelidae, Cassidinae) Molecular Ecology 13:2405 - 2420.
Bordenstein, S.R., D.H.A. Fitch and J.H. Werren. 2003. Absence of Wolbachia in Nonfilariid Nematodes. J. Nematol. 35(3):266-270.
Bordenstein, S.R., J.J. Uy and J.H. Werren. 2003. Host genotype determines Wolbachia cytoplasmic incompatibility type in Nasonia. Genetics 164:223-233.
Baudry, E., K. Emerson, T. Whitworth and J.H. Werren. 2003. Wolbachia and genetic variability in the birdnest blowfly Protocalliphora sialia. Mol. Ecol. 12:1843-1854.
Baldo, L., J.D. Bartos, J.H. Werren, C. Bazzocchi, M. Casiraghi, and S. Panelli. 2003. Different rates of nucleotide substitutions in Wolbachia from arthropods and nematodes: arms race or host range? Parasitologia 44:179-187.
Werren, J.H. 2003. Invasion of the gender benders. Nat. Hist. 112:58-63.
Gottlieb Y, E. Zchori-Fein, J.H. Werren, and T. Karr. 2002. Diploidy restoration in Wolbachia-infected Muscidifurax uniraptor. (Hymenoptera: Pteromalidae). J. Invert. Pathol. 81:166-174.
Casiraghi M., J.W. McCall, L. Simoncini, L.H. Kramer, L. Sacchi, C. Genchi, J.H. Werren, C. Bandi. 2002. Tetracycline treatment and sex-ratio distortion: a role for Wolbachia in the moulting of filarial nematodes? Int. J. Parasit. 32 (12):1457-1468.
Telschow, A., P. Hammerstein and J.H. Werren. 2002. The effect of Wolbachia on genetic divergence between populations: mainland-island model. Integr. Comp. Biol. (2):340-351.
Telschow, A., P. Hammerstein and J.H. Werren. 2002. The effect of Wolbachia on genetic divergence between populations: models with two way migration. Amer. Nat. 160:S54-S66.
Lawson, E.T., T.A. Mousseau, R. Klaper, M.D. Hunter, and J.H. Werren. 2001. Rickettsia associated with male-killing in a buprestid beetle. Heredity 86:497-505.
Hurst, G.D.D. and J.H. Werren. 2001. The role of selfish genetic elements in eukaryotic evolution. Nat. Rev. 2:597-606.
Werren, J.H. and J. Bartos. 2001. Recombination in Wolbachia. Curr. Biol. 11: 431-435.
Bordenstein, S.R., F.P. O'Hara and J.H. Werren. 2001. Wolbachia-induced bidirectional incompatibility precedes other hybrid incompatibilities in Nasonia. Nature 409:707-710.
Shoemaker, D.D., K.G. Ross, L. Keller, E.L. Vargo and J.H. Werren. 2000. Wolbachia infections in native and introduced populations of fire ants (Solenopsis spp.). Insect Mol. Biol 9:661-674.
Werren, J.H. and D.W. Windsor. 2000. Wolbachia infection frequencies in insects: evidence of a global equilibrium? Proc. Roy. Soc. Lond. B. 267:1277-1285.
Slatko, B., S.L. O'Neill, A.L. Scott, J.H. Werren, and M.L. Blaxter. 1999. The Wolbachia genome consortium. Micro. Comp. Genomics 4:161-165.
West, S.A., J.M. Cook, J.H. Werren and H.C.J. Godfray. 1998. Wolbachia in two host-parasitoid communities. Mol. Ecol. 7:1457-1465.
Werren, J.H. and L. Beukeboom. 1998. Sex determination, sex ratios and genetic conflict. Ann. Rev. Ecol. Syst. 29:233-261.
Bordenstein, S.R. and J.H. Werren. 1998. Effects of A and B Wolbachia and host genotype on interspecies cytoplasmic incompatibility between two Nasonia species. Genetics 148:1833-1844.
Werren, J.H. 1998. Wolbachia and speciation. in Endless Forms: Species and Speciation (D. Howard and S. Berlocher, eds), pp. 245-260. Oxford University Press.
Werren, J.H. and S. O'Neill. 1997. The evolution of heritable symbionts. in Influential Passengers: Inherited Microorganisms and Arthropod Reproduction (S. O'Neill, A. Hoffman and J.H. Werren, eds), Oxford University Press.
Werren, J.H. 1997. Biology of Wolbachia. Ann. Rev. Entom. 42:587-609.
Perrot-Minnot, M.-J., L.R. Guo and J.H. Werren. 1996. Single and double infections of Wolbachia in the parasitic wasp Nasonia vitripennis: Effects on compatibility. Genetics 143:961-972.
Werren, J.H., D. Windsor, and L.R. Guo. 1995. Distribution of Wolbachia among neotropical arthropods. Proc. Royal Soc. London B. 262:197-204.
Werren, J.H., W. Zhang, and L.R. Guo. 1995. Evolution and phylogeny of Wolbachia bacteria: reproductive parasites of arthropods. Proc. Royal Soc. London B 261:55-71.
Werren, J.H., G.D.D. Hurst, W. Zhang, J.A.J. Breeuwer, R. Stouthamer and M.E.N. Majerus. 1994. Rickettsial relative associated with male-killing in the ladybird beetle (Adalia bipunctata). J. Bacteriol. 176:388-394.
Breeuwer, J.A.J. and J.H. Werren. 1993. Cytoplasmic incompatibility and bacterial density in Nasonia vitripennis. Genetics 135:565-574.
Stouthamer, R. and J.H. Werren. 1993. Microbes associated with parthenogenesis in wasps of the species Trichogramma. J. Invert. Pathol. 61:6-9.
Stouthamer, R., J.A.J. Breeuwer, R.F. Luck and J.H. Werren. 1993. Molecular identification of parthenogenesis associated microorganisms. Nature 361:66-68.
Breeuwer, J.A.J., R. Stouthamer, S.M. Burns, D.A. Pelletier, W.G. Weisburg and J.H. Werren. 1992. Phylogeny of cytoplasmic incompatibility microorganisms in the parasitoid wasp genus Nasonia (Hymenoptera: Pteromalidae) based on 16S ribosomal DNA sequences. Insect Mol. Biol. 1(1):25-36.
Breeuwer, H. and J.H. Werren. 1990. Microorganisms associated with chromosome destruction and reproductive isolation between two insect species. Nature 346: 558-560.
Werren, J.H., S.K. Skinner and A. Huger. 1986. Male-killing bacteria in a parasitic wasp. Science 231:990-992.
U of R Biology
Last modified: September 22, 2006