Digest: Experimental evidence of gene flow impacts on host adaptation to a parasite.

Does gene flow disrupt or facilitate the evolution of parasite resistance in host populations? Lewis et al. use a host-parasite system consisting of Caenorhabditis elegans (host) and Serratia marcescens (parasite) to test the effect of gene flow on adaptation. They find that gene flow from parasite-resistant host populations with divergent genetic backgrounds promotes adaptation to parasites (increased resistance). Findings from this study can be used to address more complex cases of gene flow and can be applied in conservation efforts.