Overlooked Broad-Host-Range Vector Particles in the Environment

Abstract

Horizontal gene transfer (HGT) has been proven to have a much stronger impact than mutation in the microbial world. Evidence of HGT is currently expressed as comparative sequence homology, whereas a substance with residing transfer initiative remains ambiguous. The simultaneous transfer of multiple genes could have more profound impacts than single-gene exchange on the evolutionary processes, but such data are still insufficient. Although three novel modes of HGT mechanisms have come to light---gene transfer agents (GTAs), membrane vesicles (MVs), and intercellular nanotubes (Ins)---the classic concepts of transformation, transduction, and conjugation must not be ignored.