Genomic scale analysis of lateral gene transfer in Apicomplexan parasites: insights into early eukaryotic evolution, host-pathogen interaction and drug target development
© Peixoto and Roos; licensee BioMed Central Ltd. 2007
Published: 20 November 2007
The protozoan phylum Apicomplexa is comprised of >5000 species, including Toxoplasma gondii (a prominent opportunistic infection in AIDS), and the Plasmodium parasites responsible for malaria. Complete genome sequences are now available for several apicomplexan species, including both T. gondii and Plasmodium falciparum, making it possible to exploit comparative phylogenomic tools for insight into adaptations associated with intracellular parasitism, and in order to identify targets for therapeutic development. These parasites harbor a novel organelle, the 'apicoplast', which was acquired by endosymbiotic capture of a eukaryotic alga, and thus provides a dramatic example of lateral gene transfer (LGT). In order to determine the overall impact of LGT, we have employed phylogeny reconstruction to detect transfers on a genomicscale. Trees have been constructed for all genes in the Toxoplasma and Plasmodium genomes, and compared with a whole genome species treederived from 55 taxa represented in the orthologous protein database OrthoMCL-DB . Non-apicomplexan specific ortholog groups containing4 to 100 sequences were examined, pruning outlying species based on their degree of connectivity to the group as a whole, and robustness of the resulting tree.
This article is published under license to BioMed Central Ltd.