Identification of a novel chromosomal region associated with infectious hematopoietic necrosis (IHN) resistance in rainbow trout Oncorhynchus mykiss

Abstract

Infectious hematopoietic necrosis (IHN) is an acute, systemic, rhabdoviral disease of salmonid species. To date, the effective approach in preventing or treating this epizootic disease is unknown. In this study, a genetic cross was established to elucidate the genetic markers associated with IHN resistance in rainbow trout Oncorhynchus mykiss. An IHN-resistant paternal strain of was crossed to a susceptible maternal strain to produce a F1 generation. Mating F1 males back to the maternal strain created F2, a backcross generation. Five backcross families were generated and IHNV was challenged on 92 individuals of each family. Linkage analysis was performed on the backcross families using 96 microsatellite markers from 25 linkage groups. LOD score as well as p values using the Pearson goodness of χ2- test were calculated to identify the chromosomal regions associated with IHN resistance. The highest LOD score of 0.952 (θ = 0.39) was obtained in one backcross family. A novel chromosomal region (p = 0.011) on linkage group 2 consists of a cluster of 4 microsatellite markers, OmyFGT3TUF, OmyFGT25TUF, OmyRGT35TUF and BFRO0001, and they were identified as a potential region for quantitative trait loci of IHN resistance in rainbow trout.