Parasite genetic distance and local adaptation in co-evolving bacteria-bacteriophage populations
Scanlan, Pauline D.
Hall, Alex R.
Antagonistic co-evolution between hosts and parasites can lead to local adaptation (LA) such that parasite fitness is greatest in sympatric hosts (or vice versa). The magnitude of LA typically increases with geographical distance, which is assumed to be because genetic (and hence phenotypic) distance increases with geographical distance. Here, we explicitly test the relationships between parasite genetic and phenotypic distance and LA using isolates of co-evolved viral parasites (lytic bacteriophage phi 2) and the host bacterium Pseudomonas fluorescens SBW25. We find positive relationships between parasite genotype and infectivity phenotype, but the strength of the relationship was greater when infectivity was defined by the identity of hosts that could be infected rather than the actual number of hosts infected (host range), and when measurements were compared within rather than among populations. Crucially, we find a monotonic relationship between LA and genetic distance across phage isolates from different populations, although in contrast to many geographical studies, parasite LA decreased with genetic distance. These results can be explained by the fact that bacteria can rapidly adapt to phage infectivity mutations, but that evolved resistance has a degree of specificity to the local phage population. Our results show that antagonistic co-evolution alone can result in predictable links between genetic distance and host-parasite local adaptation.
Antagonistic coevolution , Pathogen metapopulation , Host , Evolution , Specificity , Infectivity , Environment , Virulence , Selection , Patterns , Bacteria , Bacteriophages , Co‐evolution , Experimental evolution , Host–parasite interactions , Local adaptation
Scanlan, P. D., Hall, A. R. and Buckling, A. (2017) 'Parasite genetic distance and local adaptation in co-evolving bacteria–bacteriophage populations', Molecular Ecology, 26(7), pp. 1747-1755. doi: 10.1111/mec.13897
© 2016 John Wiley & Sons Ltd. This is the peer reviewed version of the following article: Scanlan, P. D., Hall, A. R. and Buckling, A. (2017), Parasite genetic distance and local adaptation in co‐evolving bacteria–bacteriophage populations. Mol Ecol, 26: 1747-1755, which has been published in final form at https://doi.org/10.1111/mec.13897. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.