Insights into the evolution of parasite resistance and susceptibility in New Zealand snails

Host-parasite interactions provide valuable insights into the immune system, mechanisms of maintaining genome diversity, and the consequences of rapid coevolution in nature. Studying host-parasite interactions is vital to our understanding of evolution and can be especially useful in understanding the causes and evolutionary trends of zoonotic disease. Although we know that many invertebrates are intermediate hosts for harmful parasites (e.g. schistosomiasis-causing parasites and their intermediate host, Biomphalaria glabrata), we don’t know the genetic mechanisms involved in the coevolution between those parasites and their invertebrate hosts.

My goal is to use the Potamopyrgus antipodarum-Atriophallophorus winterbourni system, a snail-trematode system famous as a model system for studying the effects of host-parasite interactions on the evolution of sexual reproduction, to investigate the genetic basis behind the host’s response to parasitism. I used newly completed genome assemblies to characterize genes that are being expressed at different levels in response to parasitism, which provides evidence of specific genes involved in P. antipodarum’s immune system. I found population specific responses to parasitism and rapid selection in the immune genes found through this analysis, relative to a set of comparison genes. These results provide a valuable insight into what genes may be involved in parasite response in snails, and in the future, the genes identified in this study could be used in targeted genetic studies to better understand the mechanisms of rapid host-parasite coevolution.