A near-complete chromosome from a bacterial pathogen integrated into the genome of its arthropod vector
- 1University of Liverpool
Abstract
Lateral gene transfer (LGT) from organellar to eukaryotic genomes is ubiquitous, resulting in the presence of widespread nuclear mitochondrial DNA segments (NUMTs) and/or plastid gene transfers. While LGT from bacterial associates of eukaryotes is generally less common, many arthropod genomes are littered with LGT originating from Wolbachia (order Rickettsiales) - a vertically transmitted, obligate intracellular symbiont of invertebrates. This contrasts with Rickettsia, a related genus including many important human pathogens, which has not been shown to promulgate LGT within its arthropod vectors. Here, we present the 8.6 Gb genome of a cell line derived from A. variegatum (the tropical bont tick), which is the primary vector of Rickettsia africae (agent of African tick-bite fever). In addition to numerous NUMTs and diverse families of transposable elements, an almost-complete chromosome of R. africae origin was identified in the cell line genome, localised to the putative sex chromosome. Sequencing of field-collected A. variegatum confirmed the presence of this large LGT in wild ticks, although the absence of transferred genes from the R. africae plasmid provided a means to differentiate LGT from genuine rickettsial infections. These findings highlight the imperative to consider the possibility of LGT when screening vectors for pathogens by PCR.
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BibTeX
@misc{khoo2026nearcomplete,
title = {{A near-complete chromosome from a bacterial pathogen integrated into the genome of its arthropod vector}},
author = {J. J. Khoo and A. Y. Beliavskaia and A. Ludwig and M. A. Whitehead and A. M. Al-Khafaji and C. S. Hartley and M. Kazimirova and G. S. Bah and A. Frederik and I. Cahyani and M. W. Loose and L. Bell-Sakyi and A. C. Darby and B. Makepeace},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.16.751987},
url = {https://www.biorxiv.org/content/10.64898/2026.09.16.751987v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - A near-complete chromosome from a bacterial pathogen integrated into the genome of its arthropod vector
AU - J. J. Khoo
AU - A. Y. Beliavskaia
AU - A. Ludwig
AU - M. A. Whitehead
AU - A. M. Al-Khafaji
AU - C. S. Hartley
AU - M. Kazimirova
AU - G. S. Bah
AU - A. Frederik
AU - I. Cahyani
AU - M. W. Loose
AU - L. Bell-Sakyi
AU - A. C. Darby
AU - B. Makepeace
PY - 2026
DA - 2026/09/16
PB - bioRxiv
DO - 10.64898/2026.09.16.751987
UR - https://www.biorxiv.org/content/10.64898/2026.09.16.751987v1
AB - Lateral gene transfer (LGT) from organellar to eukaryotic genomes is ubiquitous, resulting in the presence of widespread nuclear mitochondrial DNA segments (NUMTs) and/or plastid gene transfers. While LGT from bacterial associates of eukaryotes is generally less common, many arthropod genomes are littered with LGT originating from Wolbachia (order Rickettsiales) - a vertically transmitted, obligate intracellular symbiont of invertebrates. This contrasts with Rickettsia, a related genus including many important human pathogens, which has not been shown to promulgate LGT within its arthropod vectors. Here, we present the 8.6 Gb genome of a cell line derived from A. variegatum (the tropical bont tick), which is the primary vector of Rickettsia africae (agent of African tick-bite fever). In addition to numerous NUMTs and diverse families of transposable elements, an almost-complete chromosome of R. africae origin was identified in the cell line genome, localised to the putative sex chromosome. Sequencing of field-collected A. variegatum confirmed the presence of this large LGT in wild ticks, although the absence of transferred genes from the R. africae plasmid provided a means to differentiate LGT from genuine rickettsial infections. These findings highlight the imperative to consider the possibility of LGT when screening vectors for pathogens by PCR.
ER -