Project description:The study was designed to investigate the impacts of hatchery spawning and rearing on steelhead trout (Oncorhynchus mykiss) versus the wild fish on a molecular level. Additionally, epigenetic differences between feeding practices that allow slow growth and fast growth hatchery trout were investigated. The sperm and RBC DNA both had a large number of DMRs when comparing the hatchery versus wild steelhead trout populations. Interestingly, the DMRs were cell type specific with negligible overlap. Slow growth compared to fast growth steelhead also had a larger number of DMRs in the RBC samples. Observations demonstrate a major epigenetic programming difference between the hatchery and wild fish populations, but negligible genetic differences. Therefore, hatchery conditions and growth rate can alter the epigenetic developmental programming of the steelhead trout, which may correlate to the phenotypic variations observed.
Project description:To identify gene expression differences between Oncorhynchus mykiss that migrate and those that reside in freshwater, we compared gill transcriptomes of fish prior to release from a hatchery with those of fish recaptured eight days post-release while all fish were still in freshwater, but some were captured next to the hatchery (non-migrants) and others were captured moving toward the ocean (migrants). The in-hatchery sampling method represents a highly similar environment for all the fish, and allows for the determination of activated genes predictive of smolting programs prior to release into streams. Morphological (e.g. color) and physiological (gill NaCl-ATPase activity) data were also obtained and correlated to gene expression differences to aid in predictions.
Project description:To identify gene expression differences between Oncorhynchus mykiss that migrate and those that reside in freshwater, we compared gill transcriptomes of fish prior to release from a hatchery with those of fish recaptured eight days post-release while all fish were still in freshwater, but some were captured next to the hatchery (non-migrants) and others were captured moving toward the ocean (migrants). The in-hatchery sampling method represents a highly similar environment for all the fish, and allows for the determination of activated genes predictive of smolting programs prior to release into streams. Morphological (e.g. color) and physiological (gill NaCl-ATPase activity) data were also obtained and correlated to gene expression differences to aid in predictions. Gill tissue was sampled for transcriptome profiling 13 days prior to two different releases from the hatchery (total sampled within hatchery n = 19). Samples were also taken eight days after the two releases near-hatchery (total in-creek n = 20) or migrating towards the ocean but still in freshwater (second release only n = 20). Finally, 48 days after the second release a final set of resident fish were sampled near the hatchery (n =10). In terms of time after release, the most parallel comparison is the second 8 day post release sample in-creek and migrating. Although all samples were obtained in freshwater, the samples with the most similar local environment are the pre-release samples.
