Plant & Animal Genomes XIII Conference

January 15-19, 2005
Town & Country Convention Center
San Diego, CA

Assignment Of The Rainbow Trout Linkage Groups To Specific Chromosomes

Ruth B. Phillips¹ , Marc Noakes¹ , Jenefer DeKoning¹ , Matthew R. Morasch¹ , Kimberly A. Keatley¹ , Caird Rexroad III² , Yniv Palti² , Roy G. Danzmann³ , Krista M. Nichols⁴ , Robert E. Drew⁵ , Gary H. Thorgaard⁵

¹  School of Biological Sciences, Washington State University, Vancouver, WA 98686-9600, USA

²  USDA/ARS National Center for Cool and Cold Water Aquaculture, Kearneysville,WV 25430, USA

³  Department of Zoology, University of Guelph, Guelph, ON, N1G 2W1, CANADA

⁴  Northwest Fisheries Science Center, National Marine Fisheries, Seattle, WA 98112-2097, USA

⁵  School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA

The genetic map of rainbow trout has been linked to specific chromosomes and chromosome arms of the OSU (2N=60) strain using fluorescence in situ hybridization (FISH) with BACs containing markers from each genetic linkage group. These markers included type I genes, microsatellite loci and random BACs linked to the genetic map by SNPs. The resulting cytogenetic map helps explain differences in genetic maps based on crosses with parents of different karyotypes and chromosome-specific variation found in the recombination rates between male and female maps. Chromosome structure has a major effect on recombination rate differences between the sexes. Linkage groups of uni-armed (acrocentric) chromosomes had lower female:male recombination rates than linkage groups of biarmed (metacentric) chromosomes. Localization of selective BACs to chromosomes of hybrids between OSU and Clearwater (2N=58) and OSU and Swanson (2N=58) clonal lines showed that the strains with 58 chromosomes had a chromosome fusion involving chromosome pairs 25 and 29 from the OSU strain. BAC clones were obtained by screening the OSU and Swanson libraries. DNA was extracted, clones labeled using nick translation and hybridizations carried out according to standard methods. Images were captured with a Sensys camera and analyzed with Cytovision software (Applied Imaging, Inc.). Chromosomes were identified by size, chromosome arm ratios and using centromere probes. Supported by Grant 2002-00466 from USDA.