Donald Price (Life Sciences) was part of a team including scientists from UC Berkeley, Purdue University, University of Chicago, and Stanford University, that published an article in the October issue of Molecular Biology and Evolution titled "Horizontal Transfer of Bacterial Cytolethal Distending Toxin B Genes to Insects." They investigated the role that horizontal gene transfer events have played in the evolution of animals. They report on the horizontal gene transfer of cytolethal distending toxin B (cdtB), prokaryotic genes encoding eukaryote-targeting DNase I toxins, into the genomes of vinegar flies (Diptera: Drosophilidae) and aphids (Hemiptera: Aphididae). They found insect-encoded cdtB genes are most closely related to orthologs from bacteriophage that infect Candidatus Hamiltonella defensa, a bacterial mutualistic symbiont of aphids that confers resistance to parasitoid wasps. In drosophilids, cdtB orthologs are highly expressed during the parasitoid-prone larval stage and encode a protein with ancestral DNase activity. They show that cdtB has been domesticated by diverse insects and hypothesize that it functions in defense against their natural enemies. This manuscript was fast-tracked for publication receiving the highest enthusiasm from MBE’s reviewers and editors.
