Project 5

Recently, we published the genome sequence of Blattabacterium strain Bge, the primary endosymbiont of the cockroach Blattella germanica. We have already sequenced the genome of Blattabacterium strain Bor, from Blatta orientalis, and almost finished that from Blattabacterium strain Ccl, from the basal wood cockroach Cryptocercus cleveland. The genome of Blattabacterium strain Pam, from Periplaneta americana has also been published, and that from another Blattabacterium strain, from an Australian wood cockroach will soon be accessible. All these endosymbionts are Flavobacteria, phylogenetically very distant from gammaproteobacterial endosymbionts from other insects, whose genomes are also available. Comparative analysis of the genomes of these taxonomically diverse endosymbionts will allow us to test the hypothesis that convergent evolution is a common feature of the long-term evolution of bacterial endosymbionts of different insects.

These are (i) to compare the gene repertoire and functional classes among flavobacteria and gamma-proteobacteria evolving in hosts with specific diet behaviors (omnivores, plant or blood feeding), in order to test the hypothesis of functional convergence; (ii) to derive the metabolic networks from the endosymbionts chosen; (iii) to reconstruct the evolutionary history of these metabolisms, in order to evaluate the relative role played by contingent deletion of specific genes versus intracellular adaptation to hosts with specific diet requirements; and (iv) to derive the set of genes that are specifically related with endosymbiotic functions and also the minimal set formed by the housekeeping ones.

This is a computational biology PhD project that requires (i) a well annotated set of bacterial endosymbiont genomes, and updated available bioinformatic packages for (ii) metabolic inference (iii) phylogenetic and phylogenomic analyses and (iv) statistical testing.