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Given the growing appreciation of serious health sequelae from widespread Trichomonas vaginalis infection, new tools are needed to study the parasite's genetic diversity. To this end we have identified and characterized a panel of 21 microsatellites and six single-copy genes from the T. vaginalis genome, using seven laboratory strains of diverse origin. We have (1) adapted our microsatellite typing method to incorporate affordable fluorescent labeling, (2) determined that the microsatellite loci remain stable in parasites continuously cultured for up to 17 months, and (3) evaluated microsatellite marker coverage of the six chromosomes that comprise the T. vaginalis genome, using fluorescent in situ hybridization (FISH). We have used the markers to show that T. vaginalis is a genetically diverse parasite in a population of commonly used laboratory strains. In addition, we have used phylogenetic methods to infer evolutionary relationships from our markers in order to validate their utility in future population analyses. Our panel is the first series of robust polymorphic genetic markers for T. vaginalis that can be used to classify and monitor lab strains, as well as provide a means to measure the genetic diversity and population structure of extant and future T. vaginalis isolates.

The gut protozoan parasite, Giardia duodenalis, is the best characterized example of the most ancient eukaryotes, which are anaerobic and appear to be primitively amitochondrial. Apart from its obvious medical importance, Giardia is fascinating in its own right. Its prokaryotic-like anaerobic metabolism renders it selectively sensitive to some bacterial drugs, especially the nitroimidazoles, which are activated to form toxic radicals. Other features, including an enzyme that reduces oxygen directly to water, cysteine as the keeper of redox balance, a plasmid, and toxin-like genes are also distinctly prokaryotic-like. But, unlike prokaryotes, Giardia has a sophisticated, highly developed cytoskeleton, bounded nuclei, linear chromosomes capped with telomeric repeats, and telomere positional regulation of gene expression.

Two genotypes, assemblages A and B, of the pathogenic gut protozoan parasite Giardia lamblia infect humans. Symptoms of infection range from asymptomatic to chronic diarrhea. Giardia chromosomes have long been characterized but not until the publication of the first Giardia genome sequence was chromosome mapping work, commenced nearly two decades ago, completed. Initial mapping studies identified and ordered Not I chromosome segments (summating to 1.8 Mb) of the estimated 2 Mb chromosome 3. The resulting map was confirmed with the release of the Giardia genome sequence and this revitalized mapping. The result is that 93% of the WB isolate genome sequence has now been assigned to one of five major chromosomes, and community access to these data has been made available through GiardiaDB, the database for Giardia genomes.