%0 Journal Article
%T What Can Phages Tell Us about Host-Pathogen Coevolution?
%A John J. Dennehy
%J International Journal of Evolutionary Biology
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/396165
%X The outcomes of host-parasite interactions depend on the coevolutionary forces acting upon them, but because every host-parasite relation is enmeshed in a web of biotic and abiotic interactions across a heterogeneous landscape, host-parasite coevolution has proven difficult to study. Simple laboratory phage-bacteria microcosms can ameliorate this difficulty by allowing controlled, well-replicated experiments with a limited number of interactors. Genetic, population, and life history data obtained from these studies permit a closer examination of the fundamental correlates of host-parasite coevolution. In this paper, I describe the results of phage-bacteria coevolutionary studies and their implications for the study of host-parasite coevolution. Recent experimental studies have confirmed phage-host coevolutionary dynamics in the laboratory and have shown that coevolution can increase parasite virulence, specialization, adaptation, and diversity. Genetically, coevolution frequently proceeds in a manner best described by the Gene for Gene model, typified by arms race dynamics, but certain contexts can result in Red Queen dynamics according to the Matching Alleles model. Although some features appear to apply only to phage-bacteria systems, other results are broadly generalizable and apply to all instances of antagonistic coevolution. With laboratory host-parasite coevolutionary studies, we can better understand the perplexing array of interactions that characterize organismal diversity in the wild. 1. Introduction The story of life is a story of coevolution. Reciprocal relationships among replicators, whether competing, consuming, or cooperating, are a fundamental force driving organic diversification. Darwin clearly recognized as much. After observing Angraecum sesquipedale Thouars, a large Madagascan orchid with a foot-long nectary spur, he declared ¡°in Madagascar there must be moths with proboscises capable of extension to a length of between ten and eleven inches!¡± [1¨C3]. Darwin made this connection because he realized that the long spur was a product of coevolution, or coadaptation as he called it, between flower and moth. Orchids use nectar located at the base their spurs to entice pollinators to transfer pollen from one plant¡¯s anther to another¡¯s stigma so that fertilization can occur. However, pollinators with proboscises longer than an orchid¡¯s spur would not need to contact the flower to access its nectar and will remain free of pollen. Thus, a longer spur forces pollinators to dig deeper into the flower to drink its nectar, and more pollen
%U http://www.hindawi.com/journals/ijeb/2012/396165/