Since 2004, the genome sequencing of several domesticated animals has also been completed, which makes the study of animal genomes enter a phase of rapid development. Animal breeding has also moved from the phenotypic selection stage to the molecular breeding stage. As a molecular breeding tool for animal breed improvement, genome-wide association studies (GWAS) involve rapid scanning of the complete DNA of many samples to discover genetic variants associated with specific phenotypes. GWASs using high-density single nucleotide polymorphisms (SNPs) are a new approach with encouraging achievements in dissecting the genetic mechanisms of complex human diseases. In domestic animals, identifying causal mutations behind QTLs has been a challenge. GWAS has now been applied in the fields of livestock breeding and genetics, as an ideal technique for discovering major genes for complex traits and is a new way to study the genetic mechanisms of complex traits. Cattles – GWAS has applications for several economically important traits in cattle, including milk yield, milk quality, fertility, growth, meat quality, and carcass traits. GWAS is also important for the analysis of diseases such as classical bovine spongiform encephalopathy (BSE), bovine tuberculosis (TB), and mutations associated with bilateral deafness in cattle. Pigs – GWAS assists in the breeding of pigs by analyzing several economically important traits such as male androgen levels, fertility traits, back fat, loin muscle area and body size, fat area, and brown coat. In addition, GWAS is also beneficial in the study of sterility in pigs. Horses – Physical and physiological traits, particularly muscle phenotypes, are important. GWAS enables analysis of genetic regions associated with these economically important traits in horses, as well as with equine genetic disorders such as dwarfism, recurrent laryngeal neuropathy (RLN), and lavender foal syndrome (LFS). Sheep – GWAS enables analysis of economically important traits such as horn traits, and genetic diseases in sheep such as rickets. Chickens – GWAS can be applied to the study of important economic traits such as abdominal fat, body weight, growth, egg production, and quality traits in chickens. Companion Animals – GWAS research on companion animals has focused on analyzing genetic regions associated with disease, allowing analysis of genetic regions for a wide range of genetic disorders, diseases in dogs such as degenerative myelopathy (DM), canine atopic dermatitis (cAD), arrhythmogenic right ventricular cardiomyopathy (ARVC) and intervertebral disc calcification and disc protrusion in dachshunds, and diseases in cats such as hypokalemia and craniofacial defects, genetic susceptibility to feline infectious peritonitis and susceptibility to diabetes.
Application of GWAS to Animal Breeding
Application of GWAS to Animal Breeding