The Boer goat is one of the top meat breeds in modern animal husbandry and has attracted widespread attention for its unique growth performance. However, the genetic basis of muscle development in the Boer goat remains obscure. In this study, we identified specific structural variants in the Boer goat based on genome-wide selection signals and analyzed the basis of the molecular heredity of related candidate genes in muscle development. A total of 9 959 autosomal copy number variations (CNVs) were identified through selection signal analysis in 127 goat genomes. Specifically, we confirmed that the highest signal CNV (HSV) was a chromosomal arrangement containing an approximately 1.11 Mb (CHIR17: 60062304-61171840 bp) duplicated fragment inserted in reverse orientation and a 5 362 bp deleted region (CHIR17:60145940-60151302 bp) with overlapping genes (e.g., ARHGAP10, NR3C2, EDNRA, PRMT9, and TMEM184C). The homozygous duplicated HSV genotype (+/+) was found in 96% of Boer goats but was not detected in Eurasian goats and was only detected in 4% of indigenous African goats. The expression network of three candidate genes ( ARHGAP10, NR3C2, and EDNRA) regulating dose transcription was constructed by RNA sequencing. Results indicated that these genes were involved in the proliferation and differentiation of skeletal muscle satellite cells (SMSCs) and their overexpression significantly increased the expression of SAA3. The HSV of the Boer goat contributed to superior skeletal muscle growth via the dose effects of overlapping genes.
作为全球畜牧业中顶级肉用经济动物品种之一，波尔山羊优异的生长性能备受各界关注。然而，至今波尔山羊优良的肌肉发育特性的遗传基础仍不清楚。该研究利用全基因组选择信号技术鉴定波尔山羊特定的结构变异并分析了其肌肉发育相关候选基因遗传基础。结果显示，在127个山羊基因组中共鉴定出9959个常染色体拷贝数变异(CNVs)。其中最高信号的CNV (HSV)是一段包含大约1.11 Mb染色体片段(CHIR17: 60062304–61171840bp)反向插入并替换一段5362bp的区域(CHIR17: 60145940–60151302bp)，并覆盖多个关键候选基因( ARHGAP10、NR3C2、EDNRA、PRMT9、TMEM184C)。基因型频率结果显示，HSV纯合变异重复基因型(+/+)在波尔山羊给群体中占96%，但在欧、亚山羊中未发现，非洲本地山羊中仅占4%的。另外，利用慢病毒转染及RNA-seq技术，构建3个主要候选基因( ARHGAP10、NR3C2和 EDNRA)的转录剂量过表达的基因调控网络，并证实这系列基因广泛参与了骨骼肌卫星细胞(SMSCs)的增殖和分化，且3个基因的过表达均显著提高了下游SAA3基因表达剂量。综上，该研究利用全基因组与细胞生物学技术手段，明晰了波尔山羊特有的结构变异HSV，并证实了其所覆盖基因可能在山羊肌肉细胞的发育具有重要作用基础，该研究将助于我们进一步理解山羊肌肉细胞的生长发育遗传机制的同时，为我国肉用山羊育种贡献了新的遗传标记。.
Keywords: Boer goat; CNV; Muscle development; SMSCs.