Development of forward genetics in Toxoplasma gondii

Int J Parasitol. 2009 Jul 1;39(8):915-24. doi: 10.1016/j.ijpara.2009.02.011. Epub 2009 Feb 28.


The development of forward genetics as a functional system in Toxoplasma gondii spanned more than three decades from the mid-1970s until now. The initial demonstration of experimental genetics relied on chemically induced drug-resistant mutants that were crossed by co-infecting cats, collecting oocysts, sporulating and hatching progeny in vitro. To capitalise on this, genetic markers were employed to develop linkage maps by tracking inheritance through experimental crosses. In all, three generations of genetic maps were developed to define the chromosomes, estimate recombination rates and provide a system for linkage analysis. Ultimately this genetic map would become the foundation for the assembly of the T. gondii genome, which was derived from whole genome shotgun sequencing, into a chromosome-centric view. Finally, application of forward genetics to multigenic biological traits showed the potential to map and identify specific genes that control complex phenotypes including virulence.

Publication types

  • Historical Article
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Animals
  • Cats
  • Chromosome Mapping / history*
  • Chromosome Mapping / methods
  • Crosses, Genetic
  • Drug Resistance
  • Genetics, Population / history*
  • Genome, Protozoan*
  • History, 20th Century
  • Humans
  • Life Cycle Stages*
  • Mice
  • Phylogeny
  • Polymerase Chain Reaction
  • Polymorphism, Restriction Fragment Length / genetics
  • Protozoan Proteins / genetics
  • Restriction Mapping / history
  • Restriction Mapping / methods
  • Toxoplasma / genetics*
  • Toxoplasma / growth & development
  • Toxoplasma / pathogenicity
  • Toxoplasmosis / history
  • Toxoplasmosis / parasitology
  • Virulence


  • Protozoan Proteins