Wubuli Ayixie, Su Yi, Yao Xinkui, Meng Jun, Wang Jianwen, Zeng Yaqi, Li Linling, Ren Wanlu
College of Animal Science, Xinjiang Agricultural University, Urumqi 830052, China.
Xinjiang Key Laboratory of Equine Breeding and Exercise Physiology, Urumqi 830052, China.
Biology (Basel). 2025 Sep 8;14(9):1216. doi: 10.3390/biology14091216.
The Kazakh horse, a versatile breed, is renowned for stable genetic performance and strong tolerance to coarse feed. Sex is a key factor influencing skeletal muscle development. However, the mechanisms underlying sex-specific regulation of equine muscle growth remain obscure. This study employed transcriptomic analysis to investigate sex-associated molecular differences in skeletal muscle of Kazakh horses. The experimental cohort comprised four three-year-old Kazakh stallions and four three-year-old Kazakh mares. After slaughter, six groups of muscle samples were collected immediately, including the longissimus dorsi, rectus abdominis, and diaphragm muscles of both sexes, with four biological replicates per group. RNA-seq analysis revealed 361, 230, and 236 differentially expressed genes (DEGs) in the longissimus dorsi of stallion Kazakh horses (Mb) vs. the longissimus dorsi of mare Kazakh horses (Gb), the rectus abdominis of stallion Kazakh horses (Mf) vs. the rectus abdominis of mare Kazakh horses (Gf), and the diaphragm of stallion Kazakh horses (Mg) vs. the diaphragm of mare Kazakh horses (Gg), respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses indicated that DEGs such as , , , and were primarily enriched in muscle system processes (BP), contractile fibers (CC), and adenosine ribonucleotide binding (MF). Furthermore, these genes were significantly associated with pathways such as the Cytoskeleton in muscle cells and the Thyroid hormone signaling pathway. The data demonstrate pronounced sex-related differences in gene expression and muscle structure in Kazakh horses, likely mediated by cytoskeleton-associated genes. Notably, , , , and may act as key regulators of sex-specific muscle development. These findings provide molecular insights into the mechanisms underlying sexual dimorphism in equine muscle growth.
哈萨克马是一个多用途品种，以稳定的遗传性能和对粗饲料的强耐受性而闻名。性别是影响骨骼肌发育的关键因素。然而，马肌肉生长的性别特异性调控机制仍不清楚。本研究采用转录组分析来研究哈萨克马骨骼肌中与性别相关的分子差异。实验队列包括四匹三岁的哈萨克种公马和四匹三岁的哈萨克母马。屠宰后，立即收集六组肌肉样本，包括两性的背最长肌、腹直肌和膈肌，每组有四个生物学重复。RNA测序分析分别揭示了哈萨克种公马背最长肌（Mb）与哈萨克母马背最长肌（Gb）、哈萨克种公马腹直肌（Mf）与哈萨克母马腹直肌（Gf）、哈萨克种公马膈肌（Mg）与哈萨克母马膈肌（Gg）中361、230和236个差异表达基因（DEG）。基因本体论（GO）和京都基因与基因组百科全书（KEGG）富集分析表明，诸如 、 、 和 等DEG主要富集在肌肉系统过程（BP）、收缩纤维（CC）和腺苷核糖核苷酸结合（MF）中。此外，这些基因与肌肉细胞中的细胞骨架和甲状腺激素信号通路等途径显著相关。数据表明哈萨克马在基因表达和肌肉结构上存在明显的性别相关差异，可能由细胞骨架相关基因介导。值得注意的是， 、 、 和 可能作为性别特异性肌肉发育的关键调节因子。这些发现为马肌肉生长中性别二态性的潜在机制提供了分子见解。
