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Clonal Rainbow Trout

Clonal Rainbow Trout Lines at Washington State University

Gary Thorgaard    Sandra Ristow
Department of Zoology    Department of Animal Sciences
Washington State University    Washington State University
Pullman WA 99164-4236    Pullman WA 99164-6310
Email:    Email:

Clonal lines of rainbow trout have been developed at Washington State University using the chromosome set manipulation techniques of androgenesis and gynogenesis. Androgenesis involves irradiating eggs with gamma radiation before fertilization, followed by a heat or pressure shock treatment to block the first cleavage division. An advantage of androgenesis is that it allows lines to be recovered from cryopreserved sperm. The isogenicity of the lines has been confirmed using multilocus RFLP studies (3,7).

Rainbow trout are a major biomedical research animal for cancer, immunology and toxiciology research. They are also advantageous because of the large amount of research that has been carried out with them related to aquaculture and sport fisheries. Rainbow trout are native to the Pacific coast of North America and Siberia and significant native populations till exist throughout much of the species range

Specific attributes of the five lines:

    Oregon State University line:

      Sex chromosome type: XX (6)
      Chromosome number: 60(6)
      Origin: Shasta strain rainbow trout from Oregon State University
      Domestication status: Domesticated
      Development rate: Slow (11)
      Natural cytotoxic cell activity: Very low (10)
      Note: Several OSU lines with different mitochondnal DNA backgrounds have been produced by androgenesis (K. Brown, personal communication)

    Arlee line:

      Sex chromosome type: YY (6)
      Chromosome number: 64 (6)
      Origin: Hatchery rainbow trout from the Arlee hatchery, state of Montana
      Domestication status: Domesticated
      Development rate: Slow (7)
      Natural cytotoxic cell activity: Very low (2)

    Hot Creek line:

      Sex chromosome type: YY (6)
      Chromosome number: 60 (6)
      Origin: Hot Creek hatchery, California Department of Fish and Game
      Domestication status Domesticated
      Development rate: Slow (7)
      Natural cytotoxic cell activity: High (10)

    Swanson line:

      Sex chromosome type: YY, but XX in appearance (12)
      Chromosome number. 58 (12)
      Origin: Semi-wild, from Alaska Dept. Fish and Game Fort Richardson hatchery
      Domestication status: Semi-wild
      Development rate: Fast (7)

    Clearwater line:

      Sex chromosome type: YY (12)
      Chromosome number. 58 (12)
      Origin: Steelhead (sea-run form of rainbow trout) from Clearwater River, Idaho Domestication status: Semi-wild, from Dworshak hatchery
      Development rate: Fast (11)
      Note: Efforts are underway to use this line to understand the genetic control of smoltification, a major developmental switch (K. Nichols, pers. commun.).
  1. Young, W.P., P.A. Wheeler and G.H. Thorgaard, 1995. Asymmetry and variability of menstic characters and spotting in isogenic lines of rainbow trout. Aquaculture 137: 67-76.
  2. Ristow, S.S., L.D. Grabowski, P.A. Wheeler, D.J. Prieur and G.H. Thorgaard, 1995. Arlee line of rainbow trout (Oncorhynchus mykiss) exhibits a low level of nonspecific cytotoxic cell activity. Dev. Comp. Immunol. 19: 497-505.
  3. Young, W.P., P.A. Wheeler, R.D. Fields and G.H. Thorgaard, 1996. DNA fingerprinting confirms isogenicity of androgenetically-derived rainbow trout lines. J. Hered. 87: 77-81.
  4. Ristow,.S.S., M.M. de Avila, T.J. Baldwin, P.A. Wheeler and G. H. Thorgaard, 1996. Acceptance of skin grafts by isogenic rainbow trout (Oncorhynchus mykiss). Am. J. Vet. Res. 57: 1576-1579.
  5. Young, W.P., P.A. Wheeler, V.H. Coryell, P. Kelm and G. H. Thorgaard, 1998. A detailed linkage map of rainbow trout produced using doubled haploids. Genetics 148: 839-850.
  6. Ristow, S.S., L.D. Grabowski, C. Ostberg, B. Robison and G.H. Thorgaard, 1998. Development of long-term cell lines from homozygous clones of rainbow trout. J. Aquat. Anim. Health 10: 75-82.
  7. Robison, B.D., P.A. Wheeler and G.H. Thorgaard. Variation in development rate among clonal lines of rainbow trout (Oncorhynchus mykiss). Aquaculture (in press).
  8. Ristow, S.S., L.D. Grabowski, S.M. Thompson, G.W.Warr, S.L. Kaattari, J.M. de Avila and G.H. Thorgaard. Coding sequences of the MHC II B chain of homozygous rainbow trout ( Oncorhynchus mykiss ). Dev. Comp. Immunol. (in press).
  9. Brunelli, J.P. and G.H. Thorgaard. Sequence, expression and genetic mapping of a rainbow trout retinoblastoma cDNA. Gene: (in press).
  10. Ristow, S. Washington State University, personal communication.
  11. Robison, B. Washington State University, personal communication.
  12. Wheeler, P. Washington State University, personal communication.