title: Quantitative genetics of migration-related traits in rainbow and steelhead trout.
abstract: Rainbow trout (Oncorhynchus mykiss) exhibit remarkable life history diversity throughout their native range, and among the most evident is variation in migratory propensity. Although some populations and ecotypes will remain resident in freshwater habitats throughout their life history, others have the ability to undertake tremendous marine migrations. Those that migrate undergo a suite of behavioral, morphological, and physiological adaptations in a process called smoltification. We describe a quantitative genetic analysis of 22 growth, size, and morphological traits in addition to overall life history classification (resident or migrant) over the temporal process of smoltification in a large multi-generation experimental pedigree (n = 16,139) of migratory and resident rainbow trout derived from a wild population, which naturally segregates for migratory propensity. We identify significant additive genetic variance and covariance among the suite of traits that make up a component of the migratory syndrome in this species. Additionally, we identify high heritability estimates for the life history classifications and observe a strong negative genetic correlation between the migratory and resident life history trajectories. Given the large heritability estimates of all of the traits that segregate between migratory and resident rainbow trout, we conclude that these traits can respond to selection. However, given the high degree of genetic correlation between these traits, they do not evolve in isolation, but rather as a suite of coordinated characters in a predictable manner.
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907 Hagerman Fish Culture Experiment Station, Aquaculture Research Institute, University of Idaho, and Fishery Science Department, Columbia River Inter-Tribal Fish Commission, Hagerman, Idaho 83332.
authors.forename: Benjamin C
authors.initials: BC
authors.lastname: Hecht
authors.affiliation: Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, Washington 98112.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Hard
authors.affiliation: Ted Stevens Marine Research Institute, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Juneau, Alaska 99801.
authors.forename: Frank P
authors.initials: FP
authors.lastname: Thrower
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907 Department of Forestry and Natural Resources, Purdue University, West Lafayette, Indiana 47907 Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, Washington 98112 krista.nichols@noaa.gov.
authors.forename: Krista M
authors.initials: KM
authors.lastname: Nichols
mesh_terms: D025041:Animal Migration; D000818:Animals; D016000:Cluster Analysis; D020869:Gene Expression Profiling; D056726:Genetic Association Studies; D017686:Oncorhynchus mykiss / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development; D010375:Pedigree; D010641:Phenotype; D040641:Quantitative Trait Loci; D019655:Quantitative Trait, Heritable
keywords: anadromy; animal model; genetic correlation; heritability; steelhead trout