Heritability Estimates of Resistance to Infectious Hematopoietic Necrosis Virus (IHNV) in Two Populations of Steelhead Trout (Oncorhynchus mykiss)

Predicting the ecology and evolution of infectious diseases requires an understanding of factors that affect both pathogen transmission and host response. In wild populations, host response and transmission of a pathogen might be mediated by a population’s resistance to this disease.  If genetic variation for resistance can be characterized across populations, then models aimed at predicting the spread of a pathogen can be improved. Infectious hematopoietic necrosis virus (IHNV) is a virus endemic to the Pacific Northwest of the United States and can have devastating consequences on populations of steelhead. Here, we measured the genetic variation underlying disease resistance in two recently diverged steelhead populations that exhibit different degrees of resistance to IHNV. We created 71 families using a circular half-sib design and challenged two replicates of 24 fish per family with IHNV. We compared estimates of heritability derived using traditional models (generalized linear mixed model glmm) that assume that all survivors are resistant against a model (CURE) that assumes that a portion of the survivors might be susceptible with high endurance. The results of this data will be used to select informative families for a genome-wide analysis aiming at detecting loci or genomic regions linked to IHNV resistance.