Molecular markers associated with growth, meat, and carcass traits in sheep: a review

Sheep breeding has been a fundamental aspect of livestock farming for thousands of years, supplying humans with wool, meat, and milk. As the livestock sector adapts to contemporary needs, the increasing global demand for animal products, fueled by population growth, highlights the significance of effective breeding techniques. Growth and meat traits are a key factor in sheep breeding, directly impacting resource efficiency and breeder profitability. In this review, we have explored the advantages of molecular marker-assisted selection (MAS) and its specific applications in breeding meat sheep. We summarized research on quantitative trait loci (QTLs) and genome-wide association studies (GWAS), as well as variations in key genes, including myostatin (MSTN), insulin-like growth factor 1 (IGF-1), and calpastatin (CAST), associated with growth, meat quality, and carcass traits in sheep. The advancements in molecular breeding for meat sheep, along with improvements in sheep genetics, genomic selection, and genome editing, have enhanced our understanding of DNA markers and demonstrated the genetic diversity present in meat sheep, significantly enriching sheep breeding strategies. Improvements in sample size, phenotyping efficiency, and the integration of omics studies could enhance our understanding of gene interactions, enabling MAS technology to reach its full potential.