Comparison of transcriptomic profiles in natural populations of rodents (house mouse and black rat) along invasion routes in Senegal

We compared gene expression pro?les between anciently and recently established populations of two major invading species, the black rat Rattus rattus and the house mouse Mus musculus musculus, in Senegal. Transcriptome analyses revealed respectively 364 and 83 differentially expressed genes along the mouse and rat invasion routes. Among them, 10 and 15% were annotated with functions related to immunity. All immune-related genes detected along the mouse invasion route were over-expressed at the invasion front. Genes of the complement activation pathway were over-represented. Results were less straightforward when considering the black rat. No particular immune pathway was over-represented. In conclusion, we revealed changes in transcriptomic profiles along invasion routes. Patterns differed between invaders. They could potentially be driven by increased infection risks at invasion front for the house mouse and trade-offs between immune responses for the black rat. Our results provide a first step in identifying the immune ecoevolutionary processes potentially involved in invasion success. Overall design: Comparison of transcriptomic profiles based on pools of mRNA (extracted from spleen) for rodents sampled in anciently and recently invaded localities. We considered 2 replicates per locality and 4 localities per invasion status 'ancient vs recent establishment of populations'