Project description:Transcriptomics of environmental adaptation and survival in wild adult Pacific Sockeye Salmon (Oncorhynchus nerka) during spawning migration
Project description:The main findings of the current study were that exposing adult sockeye salmon Oncorhynchus nerka to a warm temperature that they regularly encounter during their river migration induced an mRNA-level heat shock response that is exacerbated with swimming. Similar immune defense-related responses were also observed. Microarray analyses revealed that 347 genes were differentially expressed between the cold (12-13° C) and warm (18-19° C) treated fish (P < 0.01), with stress response (GO:0006950; P = 0.014) and response to fungus (GO:0009620; P = 0.003) elevated with warm treatment, while expression for genes involved in oxidative phosphorylation (GO:0006119; P = 0.0019) and electron transport chain (GO:0022900; P = 0.00043) increased in cold-treated fish. By studying single genes with RT-qPCR, warm treatment fish from the Chilko population of O. nerka induced expression of heat shock protein (hsp) 90α, hsp90β and hsp30, as well as interferon-inducible protein (P < 0.05). A Nechako population of O. nerka with a narrower thermal tolerance window than the Chilko population showed even more pronounced responses to the warm treatment. In conclusion, it appears that during their once-in-the-lifetime migration these adult sockeye salmon encounter conditions that induce several cellular defense mechanisms. As river temperatures continue to increase, it remains to be seen whether or not these cellular defenses provide enough protection for all sockeye salmon populations.
Project description:Consequences of high temperatures and premature mortality on the transcriptome and blood physiology of wild adult sockeye salmon (Oncorhynchus nerka)
Project description:a salmonid microarray was used to characterize environmentally-regulated shifts in gene expression between ocean and river habitats in gill and liver tissues of wild migrating adult Pacific sockeye salmon (Oncorhynchus nerka). To correlate gene expression with survival, non-lethal biopsy sampling of gill tissue and microarray-based profiling was combined with biotelemetry and genetic stock identification so that transcriptomic profiles could be compared between fish reaching spawning grounds and presumed mortalities.
