Litter size is one of the most important reproductive traits of sheep, which has pronounced effects on the profit of husbandry enterprises and enthusiasm of breeders. Despite the importance of litter size, the underlying genetic mechanisms have not been entirely elucidated. Therefore, based on a high-density SNP chip, genome-wide comparative analysis was performed between two groups with different fecundity to reveal candidate genes linked to litter size via detection of homozygosity and selection signatures in Luzhong mutton sheep. Consequently, nine promising genes were identified from six runs of homozygosity islands, and functionally linked to reproduction (ACTL7A, ACTL7B, and ELP1), embryonic development (KLF5 and PIBF1), and cell cycle (DACH1, BORA, DIS3, and MZT1). A total of 128 genes were observed under selection, of which HECW1 and HTR1E were related to total lambs born, GABRG3, LRP1B, and MACROD2 to teat number, and AGBL1 to reproductive seasonality. Additionally, the presence of inbreeding depression implies the urgency of reasonable mating system to increase litter size in the present herd. These findings provide a comprehensive insight to the genetic makeup of litter size, and also contribute to implementation of marker-assisted selection in sheep.

中文翻译：

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结合基因组学方法鉴定鲁中肉羊产仔数相关基因

产仔数是羊最重要的繁殖性状之一，对养殖企业的利润和饲养者的积极性有显着影响。尽管窝产仔数很重要，但潜在的遗传机制尚未完全阐明。因此，基于高密度SNP芯片，在具有不同繁殖力的两组之间进行全基因组比较分析，通过检测鲁中羊肉的纯合性和选择特征来揭示与产仔数相关的候选基因。因此，从六个纯合岛运行中鉴定出九个有希望的基因，并且在功能上与生殖（ACTL7A、ACTL7B和ELP1）、胚胎发育（KLF5和PIBF1）和细胞周期（DACH1、BORA、DIS3和MZT1）。在选择下共观察到128个基因，其中HECW1和HTR1E与出生羔羊总数有关，GABRG3、LRP1B和MACROD2与乳头数有关，AGBL1与繁殖季节性有关。此外，近亲繁殖衰退的存在意味着合理交配系统的紧迫性，以增加当前牛群的窝产仔数。这些发现为窝产仔数的遗传构成提供了全面的见解，也有助于在绵羊中实施标记辅助选择。