Gene Transfer Agents and Defective Bacteriophages as Sources of Extracellular Prokaryotic DNA

Abstract

A large amount of extracellular DNA on the planet exists in the form of viruses and virus-like particles. Globally, these particles contain a large amount of DNA that appears to have originated from cellular organism genomes, as opposed to being truly viral. Although the exact frequencies with which packaging of cellular DNA happens and the full range of reasons for why this happens are not known, virus-like elements that package host DNA are known. These include defective phages and gene transfer agents. The potential that these elements have to contribute to the pool of extracellular prokaryotic nucleic acids is discussed in this chapter.