Photo credit: Ferme Marine du Douhet, France
FISHBOOST Results: New insights into genetic resistance to viral nervous necrosis (VNN) in European sea bass
Viral nervous necrosis in sea bass
Improving genetic resistance of farmed fish to infectious disease is one of the major goals of the FISHBOOST project. Viral nervous necrosis (VNN) is a disease that has a large negative impact on aquaculture of sea bass in several European countries. It causes major economic losses mainly in larval and juvenile stages of cultured sea bass. In the absence of efficient therapeutic treatments, selective breeding for host resistance has potential to control the disease. Improving genetic resistance of farmed fish to infectious disease is one of the major goals of the FISHBOOST project.
FISHBOOST research to understand the genetic background of VNN resistance
In a collaborative FISHBOOST experiment, a team comprising The Roslin Institute at the University of Edinburgh, and French partners Ferme Marine Du Douhet, SYSAAF, ANSES, Ifremer and INRA, made a significant breakthrough in the use of genetic markers to understand and improve resistance to VNN in sea bass.
Based on a large experimental challenge study including approximately 1,500 juvenile sea bass, surviving and dead fish were genotyped for over 10,000 single nucleotide polymorphism (SNP) markers using RAD sequencing. The heritability of resistance to VNN was estimated at 0.22, meaning that this trait can potentially be improved using selective breeding. A genome-wide association study (GWAS) was performed to map individual loci in the sea bass genome (QTL) that may explain a proportion of genetic variation in resistance. Several putative QTL were identified, implying that resistance is likely controlled by several genes, each with a relatively small effect.
Based on these results, a genomic prediction approach was taken to assess the accuracy of prediction breeding values for VNN resistance using all the SNPs simultaneously. This analysis demonstrated that breeding values can be estimated with high accuracy, significantly improving the state-of-the-art method which relies on pedigree information for breeding value prediction.
Implications for sea bass farming
The practical outcome of this research is likely to be improved selective breeding of sea bass stock to have higher resistance to VNN, potentially leading to reduction in the frequency and severity of outbreaks of this problematic disease.
More results at EAS 2016
Christos Palaiokostas (University of Edinburgh) will present these results at the FISHBOOST session of the European Aquaculture Society meeting in Edinburgh on 23rd September.
Viral nervous necrosis in sea bass
Improving genetic resistance of farmed fish to infectious disease is one of the major goals of the FISHBOOST project. Viral nervous necrosis (VNN) is a disease that has a large negative impact on aquaculture of sea bass in several European countries. It causes major economic losses mainly in larval and juvenile stages of cultured sea bass. In the absence of efficient therapeutic treatments, selective breeding for host resistance has potential to control the disease. Improving genetic resistance of farmed fish to infectious disease is one of the major goals of the FISHBOOST project.
FISHBOOST research to understand the genetic background of VNN resistance
In a collaborative FISHBOOST experiment, a team comprising The Roslin Institute at the University of Edinburgh, and French partners Ferme Marine Du Douhet, SYSAAF, ANSES, Ifremer and INRA, made a significant breakthrough in the use of genetic markers to understand and improve resistance to VNN in sea bass.
Based on a large experimental challenge study including approximately 1,500 juvenile sea bass, surviving and dead fish were genotyped for over 10,000 single nucleotide polymorphism (SNP) markers using RAD sequencing. The heritability of resistance to VNN was estimated at 0.22, meaning that this trait can potentially be improved using selective breeding. A genome-wide association study (GWAS) was performed to map individual loci in the sea bass genome (QTL) that may explain a proportion of genetic variation in resistance. Several putative QTL were identified, implying that resistance is likely controlled by several genes, each with a relatively small effect.
Based on these results, a genomic prediction approach was taken to assess the accuracy of prediction breeding values for VNN resistance using all the SNPs simultaneously. This analysis demonstrated that breeding values can be estimated with high accuracy, significantly improving the state-of-the-art method which relies on pedigree information for breeding value prediction.
Implications for sea bass farming
The practical outcome of this research is likely to be improved selective breeding of sea bass stock to have higher resistance to VNN, potentially leading to reduction in the frequency and severity of outbreaks of this problematic disease.
More results at EAS 2016
Christos Palaiokostas (University of Edinburgh) will present these results at the FISHBOOST session of the European Aquaculture Society meeting in Edinburgh on 23rd September.
