An Overview of Genomic Approaches for Characterizing the Genetic Architecture of Growth Traits in Chickens

The genomic approach applied in chicken breeding program has become powerful strategy to develop the poultry breeding industry. Over the past several decades, there has been a significant increase in applied studies about animal breeding and selection, leading to an impressive understanding of the economically important quantitative traits in livestock. Particularly, growth traits have been focused due to their high relevance to animal production. In this study, we reviewed most frequently applied genomic approaches to understanding the comprehensive architecture of growth traits in chickens. With the advancement of molecular techniques, candidate gene study, DNA marker technology emerged as finer tools for assessing the genetic variability. However, much clear resolution for understanding the quantitative traits were investigating through quantitative trait loci (QTL) mapping, expression quantitative trait loci (eQTL) mapping. Invent of Single nucleotide polymorphism marker led to develop high-density SNP array and application in Genome-wide association studies (GWAS) has become more powerful genetic tool. But, epigenetic regulation of growth traits in livestock; differentially methylation gene and their expression, microRNA (miRNA) and messenger RNA (mRNA) profiles, which has significantly influenced growth and body composition, thereby, reveals the another dimension of these traits. Near Future, application of, RNA sequencing, proteomics, nutrigenomics and endophenotypes to reveals the complexity of these polygenic traits may be more important for generating further hypotheses about the overall action on complex traits. Therefore, we discussed the experimental results of recent studies describing a black box of growth traits, which reveals the several important mechanisms, genes and genome-wide genetic variations responsible for growth traits in chicken.