Heterogeneous genetic basis of age at maturity in salmonid fishes

Understanding the genetic basis of repeated evolution of the same phenotype across taxa is a fundamental aim in evolutionary biology and has applications in conservation and management. However, the extent to which interspecific life-history trait polymorphisms share evolutionary pathways remains underexplored. Here, we address this gap by studying the genetic basis of a key life-history trait, age at maturity, in four species of Pacific salmonids (genus Oncorhynchus) that exhibit intra- and interspecific variation in this trait-Chinook Salmon, Coho Salmon, Sockeye Salmon, and Steelhead Trout. We tested for associations in all four species between age at maturity and two genome regions, six6 and vgll3, that are strongly associated with the same trait in Atlantic Salmon (Salmo salar). We also conducted a genome-wide association analysis in Steelhead to assess whether additional regions were associated with this trait. We found the genetic basis of age at maturity to be heterogeneous across salmonid species. Significant associations between six6 and age at maturity were observed in two of the four species, Sockeye and Steelhead, with the association in Steelhead being particularly strong in both sexes (p = 4.46 x 10(-9) after adjusting for genomic inflation). However, no significant associations were detected between age at maturity and the vgll3 genome region in any of the species, despite its strong association with the same trait in Atlantic Salmon. We discuss possible explanations for the heterogeneous nature of the genetic architecture of this key life-history trait, as well as the implications of our findings for conservation and management.Peer reviewe

Tree file for Supplemental Figure 1

NEXML tree file for the ten validation populations genotyped with the 91 SNP markers described in the paper

Data from: Discovery and characterization of single nucleotide polymorphisms in coho salmon, Oncorhynchus kisutch

Molecular population genetic analyses have become an integral part of ecological investigation and population monitoring for conservation and management. Microsatellites have been the molecular marker of choice for such applications over the last several decades, but single nucleotide polymorphism (SNP) markers are rapidly expanding beyond model organisms. Coho salmon (Oncorhynchus kisutch) is native to the north Pacific Ocean and its tributaries, where it is the focus of intensive fishery and conservation activities. As it is an anadromous species, coho salmon typically migrate across multiple jurisdictional boundaries, complicating management and requiring shared data collection methods. Here, we describe the discovery and validation of a suite of novel SNPs and associated genotyping assays which can be used in the genetic analyses of this species. These assays include 91 that are polymorphic in the species and one that discriminates it from a sister species, Chinook salmon. We demonstrate the utility of these SNPs for population assignment and phylogeographic analyses, and map them against the draft trout genome. The markers constitute a large majority of all SNP markers described for coho salmon and will enable both population- and pedigree-based analyses across the southern part of the species native range

Genotypic data for the ten validation populations of coho salmon

Genotypes for 91 novel SNPs from ten populations of coho salmon from the West Coast of North America in standard GENEPOP format (two-digit). Data were generated using TaqMan assays (Applied Biosystems) and a Fluidigm EP1

Data from: Discovery and characterization of single nucleotide polymorphisms in Chinook salmon, Oncorhynchus tshawytscha

No description availabl

Genotype data for Chinook salmon from California and Oregon

The file contains genotype data at 117 SNP loci for 337 Chinook salmon from the following Chinook salmon populations: Feather River spring-run (FRHsp, N=94); Butte Creek spring-run (ButteSp, N=54); Central Valley fall-run (MokBattle, N=94); Klamath/Trinity River fall-run (N=48); Lower Columbia River spring-run (KalCow, N=47). Data is in a text file in the Genepop 2-digit format

Development of a novel microhaplotype panel for steelhead/rainbow trout (Oncorhynchus mykiss) and application for phylogenetic analysis in California

The rapid advance of high-throughput sequencing has prompted a transition in wildlife and fisheries genetics from using microsatellites toward markers that are more amenable to genotyping by sequencing. Microhaplotypes are novel multi-allelic genetic markers that utilize a high-throughput genomic amplicon sequencing approach to genotype large numbers of individuals for parentage and kinship analysis and population genetic studies, including applications in monitoring and fisheries management. We describe the development of a panel of microhaplotypes for Oncorhynchus mykiss, a species of high cultural and economic importance both in its native range in the North American and the Kamchatka Peninsula of northeast Asia, and globally through introductions for aquaculture and due to its reputation as a prized sport fish among recreational fishers. The panel includes 124 loci presumed to be neutral, a marker for the sex determination locus (SdY), and 10 loci targeting previously identified adaptive genomic variants associated with important life-history traits in this species. We demonstrate that this panel provides high resolution for phylogeographic and other genetic analysis and provide an initial standardized reference population genetic baseline of California O. mykiss