Closing in on genetic resistance

Scotland: The project is being undertaken by scientists at Landcatch Natural Selection and their research partners. In 2007 the Argyll-based outfits were the first aquaculture company to be involved in work to pinpoint a gene influencing Infectious Pancreatic Necrosis (IPN).

They have since proved that sea lice resistance is inherited, subsequently producing juvenile fish which were less susceptible. This allowed breeding from selected pedigree families and increased genetic resistance in each new generation.

Delegates at the Pharmaq conference in Inverness on 25 September will hear that the new work by Landcatch and its partners means they are homing in on the relevant genes and are on target to have this science applied to their salmon eggs by 2014.

In what will be a major breakthrough for the industry, eggs and smolts could then be produced to selectively breed disease resistant salmon and other fish, as the technology can cross over to other species. The work aims to help breeders and researchers examine traits in individual fish and better understand their general survivability, omega-3 level and grilsing rates.

This involves a cutting-edge genomic selection tool – the SNP Chip – a glass slide used to analyse variations in DNA sequences, or Single Nucleotide Polymorphisms (SNPs), which act as biological markers and help scientists locate a range of genes associated with disease.

There are many millions of these variations in every species, and these can be used as milestones on the DNA map. Scientists, who previously examined only five markers for one salmon gene, can now interrogate hundreds of thousands of markers for 20,000-30,000 genes.

Dr Alan Tinch, director of genetics at Landcatch’s e-centre in Alloa, said experts have narrowed the search down to about 100 possible genes, having identified Quantitative Trait Loci (QTL) – stretches of DNA linked to the genes that underlie a trait.

He said: “We are closing in on the genes all the time. It’s a bit like us knowing the street where they live but we just don’t know yet which houses, whereas previously we only knew what town they lived in.

“We know that in that area of DNA there is something that has an effect on disease resistance and there is a technical argument for there being a gene there.”

The progress has been welcomed by Argyll and Bute MSP Michael Russell who said: “I am very pleased to see an Argyll-based company at the forefront of important research that should have strong commercial and environmental benefit. I look forward to hearing about continued progress with this work.”

Landcatch supplies genetic services and Atlantic salmon eggs and smolts to the aquaculture industry. It uses selective breeding to develop strains of salmon which can perform to ever higher levels at every stage of production, from eggs to adult fish.

The firm is part of the Hendrix Genetics multi-species food production organisation, whose mission is to help the world meet its food needs through innovative and sustainable genetic techniques which inform their breeding processes.

Their genetic research is being undertaken with Edinburgh University, Roslin Institute, Stirling Institute of Aquaculture and Glasgow University, with support from the UK Technology Strategy Board.

Landcatch general manager Neil Manchester added: “The missing genes are like our Holy Grail and finding them will have widespread positive implications. Breeding fish that are resistant to lice and disease will be an incredible achievement and a major commercial breakthrough for aquaculture and efforts to fight the war on hunger.”

Photo: Aquabounty

Source: Fishnewseu