Categories: Immune system phene

Single-gene trait/disorder: no

Mode of inheritance: Multifactorial

Disease-related: yes

Key variant known: no

Cross-species summary: Viral nervous necrosis (VNN), also called viral encephalopathy and retinopathy (VER), is caused by the betanodavirus nervous necrosis virus (NNV).

Inheritance: Delpuech et al. (2023): "European sea bass exhibits genetic variation in resistance to VNN with a heritability ranging from 0.26 to 0.43 ... "

Mapping: Delpuech et al. (2023) "generated a dataset of 838,451 single nucleotide polymorphisms (SNPs) identified from whole-genome sequencing (WGS) in the parental generation of two commercial populations (A: 2371 individuals and B: 3428 individuals) of European sea bass with phenotypic records for binary survival in a VNN challenge. For each population, three cohorts were submitted to a red-spotted grouper nervous necrosis virus (RGNNV) challenge by immersion and genotyped on a 57K SNP chip. ... [The authors] found several QTL regions that were specific to one of the populations on different linkage groups (LG), and one 127-kb QTL region on LG12 that was shared by both populations and included the genes ZDHHC14, which encodes a palmitoyltransferase, and IFI6/IFI27-like, which encodes an interferon-alpha induced protein."
Mukiibi et al. (2025) "employed integrative analyses of multiple functional genomics assays in European sea bass.  ...  The estimated heritability of VNN resistance was high (h² ~ 0.40), and a major QTL explaining up to 38% of the genetic variance of the trait was confirmed on chromosome 3, with individuals with the resistant QTL genotype showing a 90% survivability against a VNN outbreak. Whole-genome resequencing analyses narrowed the location of this QTL to a small region containing 4 copies of interferon alpha inducible protein 27-like 2A (IFI27L2A) genes, and one copy of the interferon alpha inducible protein 27-like 2 (IFI27L2) gene. RNA sequencing revealed a clear association between the QTL genotype and the expression of two of the IFI27L2A genes, and the IFI27L2 gene."

Markers: Mukiibi et al. (2025) "The SNP variant CHR3:10,077,301, through modulation of IFI27L2 and IFI27L2A genes, is likely the causative mutation underlying resistance to VNN in European sea bass."