The bacterial genus Kingella includes pathogenic species that secrete a toxin called RtxA, which is absent in commensal species. Here, Morreale et al. identify key steps in the evolutionary transition from commensal to pathogen, including horizontal gene transfer of the toxin-encoding genes, co-option of an existing secretion system, and gene duplication.
- Daniel P. Morreale
- Eric A. Porsch
- Paul J. Planet
