Bioscience Methods 2025, Vol.16, No.2, 83-99 http://bioscipublisher.com/index.php/bm 86 Muscle-specific microRNAs are also important molecular participants. For example, miR-206 and miR-1 promote myogenic differentiation during myogenesis, while some miRNAs (such as the miR-29 family) affect fiber type and matrix remodeling (Xu et al., 2023). It is worth mentioning that long non-coding RNAs (lncRNAs) discovered in recent years also play a key role in muscle development. The study of Ye et al. (2023) showed that multiple lncRNAs regulate the expression of muscle genes through ceRNA mechanisms or by interacting with chromatin modification complexes. For example, specific lncRNAs were identified in the muscle development of cattle and sheep to affect muscle cell proliferation and differentiation. A study on bovine skeletal muscle by Zhang et al. (2020) found that lncRNA-403 regulates myogenesis by affecting the KRAS/Myf6 pathway; a study on small-tailed Hu sheep by Wu et al. (2020) showed that lncRNA CTTN-IT1 promoted satellite cell proliferation and differentiation by acting as a sponge for miR-29a to increase the expression of YAP1. The development of goat skeletal muscle is jointly participated by myogenic cells and stromal cells, and is precisely regulated by a series of signaling pathways, transcription factors, and non-coding RNA molecules. 2.3 Species-specific characteristics of goats Although the basic mechanisms of skeletal muscle development are common among mammals, goats as a species also show some unique characteristics. First, the composition of muscle fiber types and fat deposition patterns in goat muscle may be different from those of other livestock species. For example, goat meat is generally considered to be leaner than beef and mutton, with lower intramuscular fat content, so the meat is characterized by low fat, low cholesterol, and high protein (Ren et al., 2023). This characteristic is related to both breed genetics and the differentiation behavior of adipocytes in its skeletal muscle. Recent single-nucleus transcriptome studies have shown that intramuscular adipogenesis in goat skeletal muscle plays an important role in muscle growth and significantly affects meat quality. Zhu et al. (2024) mapped the cell map of goat longissimus dorsi muscle development and found that different FAP subpopulations showed different transcriptional characteristics in the early and late stages of intramuscular adipogenic differentiation, and identified the transcription factor TCF7L2 as a key regulatory factor in early adipogenesis. This finding suggests that the regulation of fat deposition in goat muscle may be species-specific and have a unique effect on goat meat quality. Secondly, the diversity of goat breeds also brings about differences in muscle development characteristics. After long-term domestication and breeding, goats have formed many breeds with different economic traits. Some breeds grow rapidly and have large muscle mass, while others have unique muscle flavor or produce mainly cashmere. For example, Haimen goats in my country are small and grow slowly, but have outstanding cashmere production performance (Deng et al., 2021); while South African Boer goats grow fast and have high muscle yield. These differences between breeds are reflected in skeletal muscle development, including the rate of myofiber formation, the ratio of fiber types, and the content of intramuscular fat. Therefore, species and breed specificity need to be considered when studying goat skeletal muscle development. For example, a study on Guizhou white goats compared the longissimus dorsi muscles of individuals of different weights through transcriptome sequencing, and identified differentially expressed genes closely related to muscle growth and development, such as FGF11, NOTCH1, and ADIPOQ, which were significantly upregulated in the high-weight group (An et al., 2022). These genes are involved in cell proliferation and differentiation, fat metabolism, and growth factor signaling, and may have different expression patterns in goats of different breeds or growth types. 3 Insights into Goat Muscle Development from Single-Cell Transcriptomics 3.1 Identification of cell subpopulations Single-cell RNA sequencing enables researchers to decompose complex muscle tissue into different cell subpopulations and to finely characterize the gene expression characteristics of each cell type. In goat skeletal muscle, the application of single-cell or single-nucleus transcriptome technology can identify a variety of cell types including satellite cells, myoblasts, myofibers, FAPs, immune cells, and endothelial cells. For example, Zhu et al. (2024) used single-nucleus RNA sequencing to analyze the longissimus dorsi muscle of goats at different developmental stages and constructed a detailed cell map. The results identified major cell populations such as myogenic satellite cells (MuSCs), different subtypes of fibroblasts/adipocyte precursors (FAPs), and other stromal cells. These subpopulations have significant differences at the transcriptional level, and each expresses specific
RkJQdWJsaXNoZXIy MjQ4ODYzNA==