Experimental coevolution with bacteria and phage: The Pseudomonas fluorescens—Φ2 model system

Parasites are ubiquitous in biological systems and antagonistic coevolution between hosts and parasites is thought be a major ecological and evolutionary force. Recent experiments using laboratory populations of bacteria and their parasitic viruses, phage, have provided the first direct empirical evidence of antagonistic coevolution in action. In this article we describe this model system and synthesise recent findings that address the causes and consequences of antagonistic coevolution.