Identifying Salmon Genes Helps Future Research

Some gene variants are more likely to increase the risk of disease, while others can protect against it. By increasing knowledge about genes and gene variants, researchers will be able to tailor future medical treatment and breeding conditions for salmon.

The collection of all the genes actively expressed at any one time in a particular cell is called transcription. By increasing knowledge about transcription, researchers will understand more about the growth, nutrition content and resistance to disease of the salmon. In the future, this knowledge can be used to breed salmon that are healthier and more nutritious – two factors that will have a large economic impact on the fish farming industry.

In her study, Ms Hagen-Larsen has utilised advanced methods of gene technology and molecular biology to identify genes and gene variations in both healthy and diseased salmon. In collaboration with colleagues, she has identified and sequenced salmon genes from 15 different salmon tissues. A total of over 20,000 unique sequences have been made publicly accessible in both the database of the Norwegian salmon gene project and in GenBank.

In order to clarify the progression of disease in salmon, Ms Hagen-Larsen has worked on the identification of genes that may be involved in preliminary immune response against the viral disease infectious salmon anemia (ISA). As a disease develops, many genes are involved or affected. By identifying these genes, we gain a better picture of the processes that are set in motion and a better understanding of which genes may influence the salmon's susceptibility to disease and capacity for survival.

After a trial infection using the ISA virus, Ms Hagen-Large isolated RNA amounting to the complete transcription from both diseased and healthy fish and then studied differences in the gene expression. Her study identified several hundred genes that show a change in expression as a consequence of being infected by the ISA virus.

Furthermore, Ms Hagen-Larsen's PhD-project has led to the discovery of over 500 possible DNA variations (SNPs) in the gene sequences. Her study charts these DNA variations and has thereby made a significant contribution towards drawing up a genetic chart that will be valuable for further research.

Since DNA variations can lead to changes in amino acids and thereby the proteins that are formed, these variations may have a substantial effect on factors such as growth and resistance to disease. Once the DNA variations are properly charted, they can be used to breed better and healthier farmed salmon.