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United States Department of Agriculture

Agricultural Research Service

Research Project: UTILIZATION OF GENOMICS FOR IMPROVING PRODUCTION TRAITS IN COOL AND COLD WATER AQUACULTURE

Location: Cool and Cold Water Aquaculture Research

Title: Evidence of major genes affecting resistance to bacterial cold water disease in rainbow trout using Bayesian methods of segregation analysis

Authors
item Vallejo, Roger
item Wiens, Gregory
item Rexroad, Caird
item Welch, Timothy
item Evenhuis, Jason
item Leeds, Timothy
item Janss, Luc -
item Palti, Yniv

Submitted to: Journal of Animal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 24, 2010
Publication Date: December 1, 2010
Citation: Vallejo, R.L., Wiens, G.D., Rexroad III, C.E., Welch, T.J., Evenhuis, J., Leeds, T.D., Janss, L.L., Palti, Y. 2010. Evidence of major genes affecting resistance to bacterial cold water disease in rainbow trout using Bayesian methods of segregation analysis. Journal of Animal Science. 88:3814-3832.

Interpretive Summary: Bacterial cold water disease (BCWD) causes significant economic loss in salmonid aquaculture. We previously detected genetic variation for BCWD resistance in our rainbow trout population, and a family-based selection program to improve resistance was initiated in 2005. We utilized Bayesian methods of segregation analysis to investigat evidence of major genes underlying this trait. A total of 10,603 juvenile fish from 101 families corresponding to three generations (2005, 2007 and 2009 hatch years) of the National Center for Cool and Cold Water Aquaculture (NCCCWA) population were challenged with Flavobacterium psychrophilum, the bacterium that causes BCWD. Our results indicate that 4-5 major genes contribute to the genetic variation of BCWD resistance. These findings provide the basis for designing informative crosses to identify genes affecting BCWD resistance in rainbow trout.

Technical Abstract: Bacterial cold water disease (BCWD) causes significant economic loss in salmonid aquaculture. We previously detected genetic variation for BCWD resistance in our rainbow trout population, and a family-based selection program to improve resistance was initiated at the National Center for Cool and Cold Water Aquaculture (NCCCWA) in 2005. This study investigated evidence of major trait loci affecting BCWD resistance using Bayesian methods of segregation analysis (BSA). A total of 10,603 juvenile fish from 101 full-sib families corresponding to three generations (2005, 2007 and 2009 hatch years) of the NCCCWA population were challenged by intraperitoneal injection with Flavobacterium psychrophilum, the bacterium that causes BCWD. The results from single- and multiple-QTL models of BSA indicate that 4-5 QTL each explain 18-25% of phenotypic variance; with either codominant or dominant disease-resistant alleles plus polygenic effects underlie the genetic architecture of BCWD resistance. This study also highlights the importance of polygenic background effects in the genetic variation of BCWD resistance. The polygenic heritability on the observed scale of survival status (h2 = 0.45) is slightly larger than that previously reported for rainbow trout BCWD resistance. These findings provide the basis for designing informative crosses for QTL mapping and carrying out genome scans for QTL affecting BCWD resistance in rainbow trout.

Last Modified: 7/27/2014
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