Aquaculture

What lies beneath – the complexity of salmonid genomes revealed

Dan Macqueen and Manu Kumar Gundappa contributed to a new international study.

26/11/2021

This graphic shows Genome-wide phylogenetic reconstruction of rediploidization history following the Ss4R autopolyploidization.
​ This graphic shows Genome-wide phylogenetic reconstruction of rediploidization history following the Ss4R autopolyploidization. The full figure is available through the article itself. ​

All salmonid fishes, including keystone aquaculture species like Atlantic salmon and rainbow trout, are known to have experienced a doubling of their full genetic code about 100 million years ago. This genome duplication event is a special feature of this fish group and essential to consider in studies of salmonid biology and genetics, with most genes being retained in duplicated copies.

In a new study published in Molecular Biology and Evolution, an international team led by Dr Manu Kumar Gundappa and Professor Dan Macqueen within the Roslin Aquaculture Team, compared the entire genome sequence of multiple salmonid fish species that have evolved over many tens of millions of years since the ancestral genome duplication. They reconstructed a complex evolutionary process at high resolution, where different chunks of the genome have returned from a duplicated to non-duplicated state at different times in salmonid evolution.

"We believe the salmonid mode of genome evolution we have described is not a quirk of this fish group, but may be widespread after many genome duplication events, and hence played a role in the evolution of many complex life-forms," Dan reports. "This was a challenging study that took a novel approach to use ‘big data’ approaches to study the evolution of duplicated genomes, which we are particularly proud of devising."

This paper changes our understanding of salmonid genetics, but also has implications for our broader understanding of genome evolution after duplication.

You can access the new paper in Molecular Biology and Evolution via this external link.