Genomic Prediction of Columnaris Disease Resistance in Catfish

Genetic and epigenetic regulation of growth, reproduction, disease resistance and stress responses in aquaculture

Major progress has been made with genomic and genetic studies in aquaculture in the last decade. However, research on epigenetic regulation of aquaculture traits is still at an early stage. It is apparent that most, if not all, aquaculture traits are regulated at both genetic and epigenetic levels. This paper reviews recent progress in understanding of genetic and epigenetic regulation of important aquaculture traits such as growth, reproduction, disease resistance, and stress responses. Although it is challenging to make generalized statements, DNA methylation is mostly correlated with down-regulation of gene expression, especially when at promoters and enhancers. As such, methylation of growth factors and their receptors is negatively correlated with growth; hypomethylation of genes important for stress tolerance is correlated with increased stress tolerance; hypomethylation of genes important for male or female sex differentiation leads to sex differentiation into males or females, respectively. It is apparent that environmental regulation of aquaculture traits is mediated at the level of epigenetic regulation, and such environment-induced epigenetic changes appeared to be intergenerationally inherited, but evidences for transgenerational inheritance are still limited.

What Can Genetics Do for the Control of Infectious Diseases in Aquaculture?

Simple Summary

Infectious diseases place an economic burden on aquaculture and a limitation to its growth. This state-of-the-art review describes the application of genetics and genomics as novel tools to control infectious disease in aquaculture.

Abstract

Infectious diseases place an economic burden on aquaculture and a limitation to its growth. An innovative approach to mitigate their impact on production is breeding for disease resistance: selection for domestication, family-based selection, marker-assisted selection, and more recently, genomic selection. Advances in genetics and genomics approaches to the control of infectious diseases are key to increasing aquaculture efficiency, profitability, and sustainability and to reducing its environmental footprint. Interaction and co-evolution between a host and pathogen can, however, turn breeding to boost infectious disease resistance into a potential driver of pathogenic change. Parallel molecular characterization of the pathogen and its virulence and antimicrobial resistance genes is therefore essential to understand pathogen evolution over time in response to host immunity, and to apply appropriate mitigation strategies.

First High-Density Linkage Map and QTL Fine Mapping for Growth-Related Traits of Spotted Sea bass (Lateolabrax maculatus)

Possessing powerful adaptive capacity and a pleasant taste, spotted sea bass (Lateolabrax maculatus) has a broad natural distribution and is one of the most popular mariculture fish in China. However, the genetic improvement program for this fish is still in its infancy. Growth is the most economically important trait and is controlled by quantitative trait loci (QTL); thus, the identification of QTLs and genetic markers for growth-related traits is an essential step for the establishment of marker-assisted selection (MAS) breeding programs. In this study, we report the first high-density linkage map of spotted sea bass constructed by sequencing 333 F1 generation individuals in a full-sib family using 2b-RAD technology. A total of 6883 SNP markers were anchored onto 24 linkage groups, spanning 2189.96 cM with an average marker interval of 0.33 cM. Twenty-four growth-related QTLs, including 13 QTLs for body weight and 11 QTLs for body length, were successfully detected, with phenotypic variance explained (PVE) ranging from 5.1 to 8.6%. Thirty potential candidate growth-related genes surrounding the associated SNPs were involved in cell adhesion, cell proliferation, cytoskeleton reorganization, calcium channels, and neuromodulation. Notably, the fgfr4 gene was detected in the most significant QTL; this gene plays a pivotal role in myogenesis and bone growth. The results of this study may facilitate marker-assisted selection for breeding populations and establish the foundation for further genomic and genetic studies investigating spotted sea bass.