Using Next‐Generation Sequencing to Assist a Conservation Hatchery: a Single‐Nucleotide Polymorphism Panel for the Genetic Management of Endangered Delta Smelt

Abstract

AbstractThe Delta Smelt Hypomesus transpacificus, listed as threatened under the California Endangered Species Act, has been cultured at a conservation hatchery since 2008 in response to significant declines in the wild. The conservation hatchery relies on accurate, efficacious, and reproducible molecular techniques to help maintain the captive population's overall genetic diversity and to minimize inbreeding. We created a panel of single‐nucleotide polymorphisms (SNPs) to support broodstock pedigree reconstruction and improve upon current genetic management. For the SNP discovery, we sequenced 27 broodstock samples from the 2012 spawn by using restriction site‐associated DNA sequencing (RAD‐seq). We then created a linkage map by genotyping three single‐pair crosses at 2,317 newly discovered loci with RAD‐seq. We successfully mapped 1,123 loci and identified 26 linkage groups. Fluidigm SNP Type genotyping assays were developed for 104 mapped loci that were selected for minor allele frequencies (MAFs) greater than 0.20, neutrality (Hardy–Weinberg equilibrium), and marker location. Candidates for the genotyping panel were evaluated on a Fluidigm Integrated Fluidic Circuit 96.96 and were tested for marker accuracy and the ability to correctly assign parentage. When applied in conjunction with mating records, we found that a panel of 24 independent SNPs (mean MAF = 0.47) successfully assigned 100% of tested offspring if all of the samples were genotyped at a minimum of 18 loci. Given its capacity to streamline the screening of broodstock candidates, we foresee that the new SNP parentage panel will assume an integral role in genetic management of the Delta Smelt conservation hatchery. Furthermore, genomic resources created for this study have the potential to propel further advances in studying this imperiled species.