Abstract
Postnatal muscle development involves complex transcriptional regulation that remains poorly characterized in goats. This study employed RNA-Seq to profile the Longissimus dorsitranscriptome of Leizhou Black goats across three developmental stages: birth, six months, and two years. We identified dynamic gene expression patterns, widespread alternative splicing events, and stage-specific co-expression networks that collectively orchestrate muscle maturation. A significant transcriptional shift occurred between six months and two years, marked by the downregulation of proliferation-related genes (e.g., RRM2, TOP2A) and the activation of pathways governing muscle contraction and energy metabolism. Functional enrichment analyses highlighted the importance of PI3K-Akt, PPAR, and calcium signaling pathways throughout development. Additionally, 905 novel transcripts were discovered, many enriched in mitochondrial functions, indicating incompleteness in the current goat genome annotation. Weighted gene co-expression network analysis revealed modules correlated with developmental stages, and protein-protein interaction analysis identified hub genes regulating cell cycle progression and muscle function. Key results were validated via qRT-PCR, confirming the temporal expression patterns of genes such as CYP4B1, HACD1, and ACTC1. These findings provide mechanistic insights into the transcriptional reprogramming driving postnatal muscle development and offer valuable genetic resources for improving meat production in goats through molecular breeding.