Genetics of whirling disease resistance in rainbow trout

Whirling Disease Basics

Whirling disease is caused by Myxobolus cerebralis, a pathogen accidentally introduced into the USA in 1956.

Alternative life stages of the pathogen exist: the triactinomyxon stage infects a salmonid host and the myxospore stage infects an oligochaete worm (Tubifex tubifex) host.

Clinical signs of the disease in salmonids: black tail, skeletal deformities, whirling behavior. Juveniles are most susceptible to clinical signs and mortality occurs when fish are unable to forage for food or escape predation. Rainbow trout have one of the highest degrees of susceptibility.

Project Goals

1.     Perform comparative microarray analysis of resistant (Hofer) and susceptible (Trout Lodge) rainbow trout strains to identify genes associated with whirling

          disease resistance.

                                                                                         Experimental Design

     Status:     Microarray hybridizations have been performed for both blood and skin samples. Data are currently being analyzed to determine significant

                    expression differences.

                   Three sources for microarrays: University of Victoria (16K GRASP array), Oregon State University (Marine and Freshwater Biomedical Sciences

                   Center), and Michigan State University (Dr. Weiming Li's laboratory)

2.  QTL study using backcross families [CRR X (CRR X Hofer)]

     Status:    DNA has been extracted from progeny and microsatellites (~200) are currently being tested.