October 20,  2020

Roslin: Genome explains differences in wild and farmed salmon

Researchers from the Roslin Institute and University of Aberdeen studied almost 500 salmon to identify and map large genetic variations in the genome - documenting sections that were deleted, duplicated or inverted - to reveal some that may help explain behavioural traits seen in farmed fish.

They led a major collaborative effort to map structural variation across the Atlantic salmon genome in 492 fish sampled around the world.

The team found that existing methods for identifying structural variation using genome sequencing data were not sufficiently accurate. They developed an approach, previously used in analysing human genomes, for efficiently checking every possible variation, resulting in almost 16,000 newly discovered high-confidence structural variants.

The study has shed light on common variations in DNA that affect the function and expression of many genes, including those linked to behaviour and other traits of commercial interest. Its findings build on previous discoveries of behavioural differences between farmed and wild fish. One example of this difference is that farmed fish tend to be less fearful of predators and more motivated to find food than wild fish, which underpins their faster growth rate.

Structural variations also appear to have been influenced by a duplication of the genome, which occurred in an ancestral salmonid fish some 100 million years ago.

Insights into structural variation in salmon, which can affect commercially important traits, could help inform selective breeding and support fish welfare.

"We have developed a novel method to reliably map structural variations across the salmon genome using sequencing datasets that are common in many species. These findings open the door to exploiting structural variation in salmon genetics, supporting research and applications in breeding and conservation, in addition to improving our understanding of genome biology and evolution," said Professor Dan Macqueen of the Roslin Institute.

- The Roslin Institute