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Genome-wide Association Reveals Genetic Basis for the Propensity to Migrate in Wild Populations of Rainbow and Steelhead Trout


Little is known of the genetic basis of migration despite the ecological benefits
migratory species provide to their communities and their rapid global decline due to
anthropogenic disturbances in recent years. Using next-generation sequencing of
restriction-site-associated DNA (RAD) tags, we genotyped thousands of single nucleotide
polymorphisms (SNPs) in two wild populations of migratory steelhead and resident
rainbow trout (Oncorhynchus mykiss) from the Pacific Northwest of the United
States. One population maintains a connection to the sea, whereas the other population
has been sequestered from its access to the ocean for more than 50 years by a
hydropower dam. Here we performed a genome-wide association study to identify 504
RAD SNP markers from several genetic regions that were associated with the propensity
to migrate both within and between the populations. Our results corroborate those
in previous quantitative trait loci studies and provide evidence for additional loci
associated with this complex migratory life history. Our results suggest a complex
multi-genic basis with several loci of small effect distributed throughout the genome
contributing to migration in this species. We also determined that despite being
sequestered for decades, the landlocked population continues to harbour genetic variation
associated with a migratory life history and ATPase activity. Furthermore, we
demonstrate the utility of genotyping-by-sequencing and how RAD-tag SNP data can
be readily compared between studies to investigate migration within this species.


Benjamin C. Hecht, Nathan R. Campbell, Dean E. Holecek, and Shawn R. Narum


Hecht, B.C., N.R. Campbell, D.E. Holecek, and S.R. Narum. 2012. Genome-wide association reveals genetic basis for the propensity to migrate in wild populations of rainbow and steelhead trout. Molecular Ecology 22:3061-3076.



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Journal Article