Organism
The Kinetoplastida (Euglenozoa) are unicellular flagellates that include the trypanosomatid parasites, most notably Trypanosoma brucei, T. cruzi and Leishmania spp. These organisms cause substantial mortality and morbidity in humans and their livestock worldwide as the causative agents of African sleeping sickness, Chagas disease and leishmaniasis respectively. Draft genome sequences are available for several species of both Trypanosoma and Leishmania, many of which are described elsewhere in these pages. Bodo saltans is a free-living heterotroph found worldwide in freshwater and marine habitats. It is a kinetoplastid, but not a trypanosomatid, and possesses the diagnostic kinetoplastid features, such as flagella sited within a specialised flagellar pocket, glycolytic processes confined to a dedicated organelle (the 'glycosome'), and the characteristic concentration of mitochondrial DNA at the base of the flagellum (the 'kinetoplast').
Objectives
The purpose of a B. saltans genome sequence is to provide an 'outgroup' for comparative genomic studies. As it is among the closest bodonid relatives of the trypanosomatids, it will provide a model of the ancestral trypanosomatid to distinguish those derived parts of the parasite genomes (i.e., unique trypanosomatid adaptations) from those which are a legacy of the free-living ancestor. This objective can be resolved into three principal comparative issues:
- Trypanosomatid disease; understanding how human trypanosomatid parasites acquired their distinct pathological strategies;
- Evolution of parasitism; understanding how the ancestral trypanosomatid became parasitic in terms of derived innovations (e.g., cell surfaces) and loss of genomic repertoire;
- Eukaryotic evolution; understanding how typical kinetoplastid features (e.g., glycosomes) evolved and how these might have been modified for parasitism.
Project
A pilot study that described ~400kbp of B. saltans genome sequenced from a whole genome fosmid library has been published (Jackson, Quail & Berriman 2008, BMC Genomics, 9:594) and the 12 fosmid inserts are available for download from our ftp site and searching on our blast server.
The WTSI is undertaking complete genome sequencing of B. saltans through a combination of multiple technologies: i) A pre-sequencing selection stage involving 'Sanger' sequencing of fosmid ends for a 4X genomic library; ii) '454' sequencing of pooled bodonid fosmid inserts to achieve a draft de novo assembly; iii) Illumina sequencing of pooled fosmid inserts and genomic DNA to provide supplementary read depth. As and when these read data are produced, it will be made available through this webpage.
