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This Article Free Via Open Access Full Text Full Text (PDF) All Versions of this Article: jas.2008-1616v1 87/11/3490    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Vallejo, R. L. Articles by Weber, G. M. PubMed PubMed Citation Articles by Vallejo, R. L. Articles by Weber, G. M.

Evidence of major genes affecting stress response in rainbow trout using Bayesian methods of complex segregation analysis¹

R. L. Vallejo^*,2, C. E. Rexroad, III^*, J. T. Silverstein^*,3, L. L. G. Janss and G. M. Weber^*

^* USDA, ARS, National Center for Cool and Cold Water Aquaculture (NCCCWA), Kearneysville, WV 25430l; and Department of Genetics and Biotechnology, University of Aarhus, DK-8830 Tjele, Denmark

² Corresponding author: roger.vallejo{at}ars.usda.gov

As a first step toward the genetic mapping of QTL affecting stress response variation in rainbow trout, we performed complex segregation analyses (CSA) fitting mixed inheritance models of plasma cortisol by using Bayesian methods in large full-sib families of rainbow trout. To date, no studies have been conducted to determine the mode of inheritance of stress response as measured by plasma cortisol response when using a crowding stress paradigm and CSA in rainbow trout. The main objective of this study was to determine the mode of inheritance of plasma cortisol after a crowding stress. The results from fitting mixed inheritance models with Bayesian CSA suggest that 1 or more major genes with dominant cortisol-decreasing alleles and small additive genetic effects of a large number of independent genes likely underlie the genetic variation of plasma cortisol in the rainbow trout families evaluated. Plasma cortisol is genetically determined, with heritabilities of 0.22 to 0.39. Furthermore, a major gene with an additive effect of –42 ng/mL (approximately 1.0 genetic SD) is segregating in this rainbow trout broodstock population. These findings provide a basis for designing and executing genome-wide linkage studies to identify QTL for stress response in rainbow trout broodstock and markers for selective breeding.

Key Words: Bayesian analysis • major gene • plasma cortisol • rainbow trout • segregation analysis • stress response