Evidence of divergent selection in a parasite due to its host immunological respond

We investigated if an immunological response (i.e. fibrosis) in threespine stickleback fish can cause divergent selection in its tapeworm Schistocephalus solidus . We pooled tapeworms from six populations in Vancouver Island (BC, Canada) and sequenced the whole genome of these pools. Then we used a modified Population Branch Statistics (PBS) technique based on F ST comparisons to find loci under divergent selection due to fibrosis. We found at least eight loci under divergent selection in tapeworm populations caused by this strong immunological respond to infection from the fish.