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ARS Home » Pacific West Area » Pullman, Washington » Animal Disease Research » Research » Research Project #439553

Research Project: Identifying Genomic Regions Associated with Chronic Wasting Disease in Elk: A Foundation for Understanding an Endemic Disease

Location: Animal Disease Research

Project Number: 2090-32000-035-005-R
Project Type: Reimbursable Cooperative Agreement

Start Date: Dec 17, 2020
End Date: Jan 31, 2022

Objective:
Chronic Wasting Disease (CWD) is a fatal degenerative prion disease that affects cervids. However, Hamir et al. (2006) demonstrated that sheep inoculated with CWD develop prion disease. Elk located in CWD endemic regions have an increased probability of contracting CWD and spreading the infectious proteins to non-endemic regions through natural migration patterns and relocation of animals for prescribed wildlife management needs. Prion diseases are very difficult to identify in infected animals until very late in the infectious process and therefore infected animals can spread the infectious agent. Prion disease in domesticated small ruminants is mitigated by selecting animals for resistant alleles located within the prion gene. However, elk do not have similar resistant alleles in their prion gene. Human and mouse studies have demonstrated genomic regions outside of the prion gene impact prion disease status. Our proposal aims to provide wildlife managers and captive breeders with additional tools to support healthy cervid populations and reduce the possibility of wildlife and domestic livestock conflicts.

Approach:
Genomic technologies have advanced such that they have expanded the opportunities in non-model species at a low per-sample cost and thus increases the statistical power of the experiment. Genotype-by-sequencing (GBS) produces a large range of genotypes randomly distributed across the genome and is based on high-throughput, next-generation sequencing of genomic fragments targeted by restriction enzymes (Elshire et. al., 2011). The technique has been successful in many diverse species such as red deer (Dodds et al., 2017), oysters (White et al., 2017), and red seaweed (Flanagan et al., 2017). Approximately 500 out of 1300 elk diagnosed as either CWD positive or negative will be genotyped with GBS and a genome-wide association study conducted to identify genomic regions outside of the prion gene associated with prion disease. A mixed model will be used to account for relatedness of the animals, sampling geographical location, and gender.