Serendipitous discovery of Wolbachia genomes in multiple Drosophila species.
BACKGROUND
The Trace Archive is a repository for the raw, unanalyzed data generated by large-scale genome sequencing projects. The existence of this data offers scientists the possibility of discovering additional genomic sequences beyond those originally sequenced. In particular, if the source DNA for a sequencing project came from a species that was colonized by another organism, then the project may yield substantial amounts of genomic DNA, including near-complete genomes, from the symbiotic or parasitic organism.


RESULTS
By searching the publicly available repository of DNA sequencing trace data, we discovered three new species of the bacterial endosymbiont Wolbachia pipientis in three different species of fruit fly: Drosophila ananassae, D. simulans, and D. mojavensis. We extracted all sequences with partial matches to a previously sequenced Wolbachia strain and assembled those sequences using customized software. For one of the three new species, the data recovered were sufficient to produce an assembly that covers more than 95% of the genome; for a second species the data produce the equivalent of a 'light shotgun' sampling of the genome, covering an estimated 75-80% of the genome; and for the third species the data cover approximately 6-7% of the genome.


CONCLUSIONS
The results of this study reveal an unexpected benefit of depositing raw data in a central genome sequence repository: new species can be discovered within this data. The differences between these three new Wolbachia genomes and the previously sequenced strain revealed numerous rearrangements and insertions within each lineage and hundreds of novel genes. The three new genomes, with annotation, have been deposited in GenBank.
Salzberg
Steven L
SL
The Institute for Genomic Research, 9712 Medical Center Drive, Rockville, MD 20850, USA. salzberg@tigr.org
Dunning Hotopp
Julie C
JC
Delcher
Arthur L
AL
Pop
Mihai
M
Smith
Douglas R
DR
Eisen
Michael B
MB
Nelson
William C
WC
D000818:Animals; D001483:Base Sequence; D004330:Drosophila / Q000382:microbiology*; D022761:Gene Transfer, Horizontal; D016680:Genome, Bacterial; D023281:Genomics; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D020577:Wolbachia / Q000145:classification / Q000235:genetics*