Specifically, our work on examines
1) How the immune response is linked to parasite resistance and, ultimately, to host and parasite fitness. One of our aims to is understand variation in immune response magnitude in a world of diverse parasites, coinfection, maternal effects, senescencing hosts and environmental variability. This work is linked to our new Wild Immunology initiative, which is born of the concern that the field of immunology has taught us a great deal about inbred model organisms in the laboratory, but perhaps too little about real species in the wild. With Daphnia, we have the capacity to study immune responses under more realistic, real-world conditions at both the genetic and cellular level. Daphnia were the subject of pioneering work on invertebrate cellular immunology, and this area was recently reborn in my lab. We also use large-scale transcriptomics (via illumina sequencing technology) to identify genes that are differentially expressed in response to pathogen invasion.
2) The genes and genomic regions subject to parasite mediated selection. We are currently embarking on new population genomic work to characterise signatures of selection across multiple entire genomes. For the interaction between D. magna and its dominant pathogen, P. ramosa, there is an exceptionally deep history of experiments on susceptibility which has revealed extensive genetic variation in both host and pathogen, including strong genotype by environment interactions and genetic specificity. It is not known, however, which genes are involved. Population genomics can be used to address this. Until very recently, genomes were sequenced and the gathering of polymorphism data was restricted to the study of candidate genes. But technological and cost barriers have now fallen to as little £1000 per genome, which will rapidly push forward the characterisation of natural selection on genomes.
