Parallelism and divergence in immune responses: a comparison of expression levels in two lakes

Abstract

Question: How do immune phenotypes differ between infected and uninfected wild individuals, and is the effect the same in different populations? Organisms: Threespine stickleback (Gasterosteus aculeatus) from two lake populations on the island of North Uist, Scotland, sampled in May 2015. Methods: For each fish, we recorded length, sex, reproductive status, condition, and parasitic infection. We measured the expression levels of eight genes that act as key markers of immune system function using qPCR, and then examined the relationship between measured factors and immune gene expression profiles within each population. Conclusions: Populations differed significantly in their immune gene expression profiles. Within each population, multiple factors, including condition, reproductive status, and Schistocephalus solidus infection levels, were found to correlate with expression levels of different arms of the immune system