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Within a general program to establish accuracy and precision in our understanding of the systematic relationships of coccidian apicomplexans, this project has four specific goals over the next four years: 1) to establish a phylogenetic framework for studying Sarcocystis epizootiology, 2) to clarify the diversity and relationships among parasites related to Toxoplasma gondii, 3) to compare the genetic structure of Toxoplasma gondii populations to those of its closest relatives and 4) to establish a reference collection of frozen parasites suitable for molecular sytematics that will support research in food safety and animal health.
Several genes will be sequenced from parasites obtained from a wide array of animals, both domesticated and wild. These will be compared to each other, and to sequences obtained from human beings, in order to define the diversity and epidemiology of these parasite species. Homologues will be characterized for genes whose global variation has already begun to be studied in T. gondii, including the Intergenic Spacer sequence between rRNA genes, beta tubulin introns, and others. Characterization of microsatellite alleles will be considered as a second approach which, although requiring a greater investment of time and resources, should provide greater population genetic resolution than is possible with current loci.