Mike Quail, Mark Blaxter, Jenna Ware, Jeremy Foster, Jen Daub, Ibrahim Kamal, Barton Slatko, The Filarial Genome Project, Bart Barrell, Neil Hall, Mehul Ganatra, David Guiliano
[
International C. elegans Meeting,
2001]
The human-infective filarial nematode parasite Brugia malayi contains three genomes : the mitochondrial genome, the genome of the rickettsia-like Wolbachia endosymbiont and the nuclear genome. We have sequenced the mitochondrial genome of Brugia malayi and compared it to the other sequenced nematode mitochondria. The genome is, as expected, very similar to that of Onchocerca volvulus , and is remarkably different from C. elegans in gene order and sequence. Phylogenetic anlysis of nematode mitochondrial DNAs conflict with phylogenies derived from nuclear genes. Most filarial species harbour an bacterium that is believed to be in mutualistic symbiosis with the nematode. The bacteria are closely related to the Wolbachia endosymbionts of arthropods. The genome of the Wolbachia endosymbiont is being mapped and sequenced by a consortium headed by Barton Slatko at New England Biolabs. The nuclear genome of B. malayi is estimated to be 100 Mbp with an expected gene number comparable to C. elegans . To date, the Filarial Genome Project has produced 22,441 ESTs from 11 different cDNA libraries from various stages of the life cycle. These are estimated to represent ~8000 different genes. As a prelude to whole genome sequencing we are now in the process of constructing a physical map for the nuclear genome. A BAC library is being end sequenced, and BAC-derived end-probes hybridised to the gridded library to create contigs in a sampling-without replacement strategy. A number of EST clones have also been hybridised. In the course of this mapping program we have defined the distribution of sattelite repeats in the library, and have identified at least two families of retrotransposon-like elements.