Molecular evolutionary studies on Trypanosoma cruzi, the agent of Chagas disease

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dc.contributor.advisorMachado, Carlos Aen_US
dc.contributor.authorFlores Lopez, Carlos Albertoen_US
dc.contributor.departmentBiologyen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2013-10-04T05:31:18Z
dc.date.available2013-10-04T05:31:18Z
dc.date.issued2013en_US
dc.description.abstractThe use of DNA sequences to address diverse evolutionary questions has increased steadily with the growing availability of genome sequence data. In this study, I make use of DNA sequence data to describe several evolutionary aspects of the protozoan parasite responsible for Chagas disease, Trypanosoma cruzi. Chagas is estimated to infect 7.7 million people and cause the deaths of approximately ten thousand people every year in Latin America. Just like many other parasitic diseases, Chagas does not have a vaccine or an effective drug treatment. In this body of work, I specifically: (1) describe the evolutionary history of the major strains of the parasite through the use of phylogenetic analyses of 32 loci and demonstrate that the parasite's original classification into two major evolutionary lineages does not reflect the evolutionary history of the parasite, (2) demonstrate that there is strong evidence for just one major recent hybridization event during the history of T. cruzi divergence and not two as previously suggested, (3) show that all major extant T. cruzi lineages diverged recently (less than 3 million years ago), well before the arrival of humans in the Americas, (4) describe a new T. cruzi lineage that appears to have diverged in North America ("TcNA"), (5) show that a significantly larger fraction of protein-coding genes have experienced positive selection in T. cruzi than in Leishmania spp., a pattern likely due to the greater versatility of T. cruzi in its host range, cell tropism and cell invasion mechanisms, and (6) illustrate a recent major expansion of a few surface protein families in T. cruzi that seem to be linked to the evolution of the parasite's ability to invade multiple cell tissues and multiple host species. These results demonstrate the applicability and power of molecular evolutionary analyses for understanding parasitic diseases.en_US
dc.identifier.urihttp://hdl.handle.net/1903/14530
dc.subject.pqcontrolledBiologyen_US
dc.subject.pqcontrolledMolecular biologyen_US
dc.subject.pqcontrolledParasitologyen_US
dc.subject.pquncontrolledChagas diseaseen_US
dc.subject.pquncontrolledEvolutionen_US
dc.subject.pquncontrolledGene duplicationen_US
dc.subject.pquncontrolledMolecular evolutionen_US
dc.subject.pquncontrolledPhylogeneticsen_US
dc.subject.pquncontrolledTrypanosomaen_US
dc.titleMolecular evolutionary studies on Trypanosoma cruzi, the agent of Chagas diseaseen_US
dc.typeDissertationen_US

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