Ruth Withler

Molecular Genetics Research Scientist
Fisheries and Oceans Canada

Current research and/or projects

I have conducted research on the genetic structure of Pacific salmon and marine fish species since 1981 using the techniques of protein electrophoresis, analysis of mitochondrial DNA, and analysis of nuclear DNA markers. The results have been applied in the identification of confiscated tissue samples and analysis of stock composition in mixed-stock fishery samples. Research on quantitative genetic variation in salmon has identified stocks with traits of interest (disease resistance, fast growth, etc.) for use in aquaculture. Of particular interest is the study of the Major Histocompatibility Complex (MHC) in fish. The MHC contains the genes that control the acquired immune response. Genetic variation in MHC genes can be used to identify disease resistant genotypes, to define population structure, and to identify important units for conservation within species.

Key publications

  1. Miller, K.M. and R.E. Withler. 1996. Sequence analysis of a polymorphic Mhc class II gene in Pacific salmon. Immunogenetics 43: 337-351.
  2. Beacham, T.D., R.E. Withler, and T.A. Stevens. 1996. Stock identification of chinook salmon using minisatellite DNA variation. Can. J. Fish. Aquat. Sci. 53: 380-394.
  3. Bower, S.M., R.E. Withler, and B.E. Riddell. 1995. Inheritance of resistance to the haemoflagellate Cryptobia salmositica by the Pacific salmon Oncorhynchus kisutch and O. nerka. J. Aquat. Anim. Health 7: 185-194.
  4. Withler, R.E., and T.D. Beacham. 1994. Genetic variation in body weight and flesh colour of coho salmon (Oncorhynchus kisutch) in British Columbia. Aquaculture 119: 135-148.
  5. Withler, R.E., and T.P.T. Evelyn. 1990. Genetic variation in susceptibility to bacterial kidney disease within and between two strains of coho salmon (Oncorhynchus kisutch). Trans. Am. Fish. Soc. 119: 1003-1009.
  6. Schweigert, J.F., and R.E. Withler. 1990. Stock identification of Pacific herring based on enzyme electrophoresis and mitochondrial DNA analysis. Am. Fish. Soc. Symp. 7: 459-469.
  7. Withler, R.E. 1987. Genetic variation in survival of chinook salmon (Oncorhynchus tshawytscha) alevins exposed to an unidentified agent of mortality. Genome 29: 839-845.
  8. Withler, R.E., W.C. Clarke, B.E. Riddell, and H. Kreiberg. 1987. Genetic variation in freshwater survival and growth of chinook salmon (Oncorhynchus tshawytscha). Aquaculture 64: 85-96.