Understanding the molecular basis of phenotypic variations in chickens is essential to elucidate how different breeds of these animals exhibit distinct characteristics, and it has important implications for avian genetic breeding programs. This study aimed to identify differences in gene expression and biological processes (BPs) between Brazilian broiler chicken (TT) and laying hen (CC) breeds, during early development (from 2.5 to 3.5 days), establishing the global transcriptional profile of the embryonic tissues that generate the wing and breast regions of the chicken. The TT and CC strains were selected at the National Center for Swine and Poultry Research of Embrapa.. Somito_RNASeq

Understanding the molecular basis of phenotypic variations in chickens is essential to elucidate how different breeds of these animals exhibit distinct characteristics, and it has important implications for avian genetic breeding programs. This study aimed to identify differences in gene expression and biological processes (BPs) between Brazilian broiler chicken (TT) and laying hen (CC) breeds, during early development (from 2.5 to 3.5 days), establishing the global transcriptional profile of the embryonic tissues that generate the wing and breast regions of the chicken. The TT and CC strains were selected at the National Center for Swine and Poultry Research of Embrapa. The RNA-seq technique was used to generate the data, which were produced by the renowned Animal Biotechnology laboratory of Esalq-USP. Our study aimed to identify genes potentially involved in shaping postnatal traits of TT and CC breeds during their development. Differentially expressed genes (DEGs) were categorized as up- and down-regulated, with the broiler breed as a comparison reference. These two sets of genes were subsequently analyzed using protein function and Gene Ontology (GO) term enrichment analysis. Regulatory networks were then built for selected biological processes, followed by a protein-protein interaction network and MCL clustering analysis to detect the main connectors in these networks. We identified several DEGs between TT and CC breeds, similarly divided into up- and down-regulated genes. Moreover, we uncovered transcriptomic profiles indicating increased cell proliferation and delayed tissue differentiation in TT broilers compared to CC layers. Our work suggests that the balance between cell proliferation and differentiation is distinct during the early development of these breeds.