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

• Published in: Journal of animal science Vol. 87; no. 11; pp. 3490 - 3505
• Main Authors: Vallejo, R.L, Rexroad, C.E. III, Silverstein, J.T, Janss, L.L.G, Weber, G.M
• Format: Journal Article
• Language: English
• Published: Champaign, IL American Society of Animal Science 01.11.2009; Am Soc Animal Sci
• Subjects: additive gene effects; alleles; Animal productions; animal stress; Animals; Bayes Theorem; Bayesian theory; Biological and medical sciences; blood chemistry; cortisol; Crowding - physiopathology; dominant genes; farmed fish; Female; freshwater fish; Fundamental and applied biological sciences. Psychology; gene segregation; Genetic Loci - genetics; genetic variation; Genotype; heritability; Hydrocortisone - blood; inheritance (genetics); linkage (genetics); major genes; Male; Models, Genetic; Oncorhynchus mykiss; Oncorhynchus mykiss - genetics; Quantitative Trait Loci - genetics; stocking rate; stress tolerance; Stress, Physiological - genetics; Terrestrial animal productions; Vertebrates; Analysis method; stress response; rainbow trout; segregation analysis; Segregation; Cortisol; plasma cortisol; Major gene; Bayesian analysis; Stress
• ISSN: 0021-8812; 1525-3163
• DOI: 10.2527/jas.2008-1616

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.