Horizontal Gene Transfer Mediated by Plasmids
Masahiro Sota and Eva M. Top
from: Plasmids: Current Research and Future Trends (Edited by: Georg Lipps). Caister Academic Press, U.K. (2008)
The ever-increasing information from bacterial genome sequences has clearly revealed frequent acquisition of genetic material from phylogenetically distant bacteria and even other organisms such as eukaryotes. The event, generally recognized as horizontal gene transfer (HGT), is now considered as a strong driving force for the evolution of bacterial genome organization and for rapid adaptation to the surrounding environments. Among the mobile elements and mechanisms of HGT, plasmids are undoubtedly critical players because of their ability to transfer by conjugation among both closely and very distantly related bacterial hosts. This feature allows them to broadly distribute genes or gene clusters that code for various host-beneficial phenotypes. This chapter introduces the features of recently characterized plasmids, with an emphasis on horizontal transfer, and the domain Bacteria (mostly Gram-positive and Gram-negative bacteria). We also describe some examples of transposable elements on plasmids, which have greatly contributed to the dissemination of phenotypic traits by HGT. The chapter ends with current research and suggestions for future studies in the areas of molecular biology, ecology and evolution of plasmids read more ...