Extensively duplicated and transcriptionally active recent lateral gene transfer from a bacterial Wolbachia endosymbiont to its host filarial nematode Brugia malayi.
BACKGROUND
Lymphatic filariasis is a neglected tropical disease afflicting more than 120 million people, while another 1.3 billion people are at risk of infection. The nematode worm Brugia malayi is one of the causative agents of the disease and exists in a mutualistic symbiosis with Wolbachia bacteria. Since extensive lateral gene transfer occurs frequently between Wolbachia and its hosts, we sought to measure the extent of such LGT in B. malayi by whole genome sequencing of Wolbachia-depleted worms.


RESULTS
A considerable fraction (at least 115.4-kbp, or 10.6%) of the 1.08-Mbp Wolbachia wBm genome has been transferred to its nematode host and retains high levels of similarity, including 227 wBm genes and gene fragments. Complete open reading frames were transferred for 32 of these genes, meaning they have the potential to produce functional proteins. Moreover, four transfers have evidence of life stage-specific regulation of transcription at levels similar to other nematode transcripts, strengthening the possibility that they are functional.


CONCLUSIONS
There is extensive and ongoing transfer of Wolbachia DNA to the worm genome and some transfers are transcribed in a stage-specific manner at biologically relevant levels.
Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA. jdhotopp@som.umaryland.edu.
Panagiotis
P
Ioannidis
Kelly L
KL
Johnston
David R
DR
Riley
Nikhil
N
Kumar
James R
JR
White
Karen T
KT
Olarte
Sandra
S
Ott
Luke J
LJ
Tallon
Jeremy M
JM
Foster
Mark J
MJ
Taylor
Julie C
JC
Dunning Hotopp
D000818:Animals; D017178:Brugia malayi / Q000235:genetics*; D004269:DNA, Bacterial / Q000235:genetics; D022761:Gene Transfer, Horizontal; D016680:Genome, Bacterial; D049751:Genome, Helminth; D016366:Open Reading Frames; D017422:Sequence Analysis, DNA; D020577:Wolbachia / Q000235:genetics*
D004269:DNA, Bacterial