Department of Genetics, Development & Molecular Biology, School of Biology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece; Genomics and Epigenomics Translational Research (GENeTres), Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Balkan Center, 57001 Thessaloniki, Greece.
Department of Genetics, Development & Molecular Biology, School of Biology, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
Animal. 2023 Mar;17(3):100723. doi: 10.1016/j.animal.2023.100723. Epub 2023 Jan 27.
Genetic architecture of sheep reproduction is increasingly gaining scientific interest due to the major impact on sheep production systems. In the present study, we conducted pedigree-based analyses and genome-wide association studies using the Illumina Ovine SNP50K BeadChip to explore the genetic mechanisms underlying the reproduction of the highly prolific Chios dairy sheep. First lambing age, total prolificacy and maternal lamb survival were selected as representative reproductive traits and estimated as significantly heritable (h = 0.07-0.21) with no evident genetic antagonism among traits. We identified novel genome-wide and suggestive significant single-nucleotide polymorphisms (SNPs) on chromosomes 2 and 12 associated with age at first lambing. The new variants detected on chromosome 2 span a region of 357.79 kb with high pairwise linkage disequilibrium estimates (r = 0.8-0.9). Functional annotation analysis revealed candidate genes, such as the collagen-type genes and the Myostatin gene, that participate in osteogenesis, myogenesis, skeletal and muscle mass development resembling the functionality of major genes affecting the ovulation rate and prolificacy. Additional functional enrichment analysis associated the collagen-type genes with multiple uterine-related disfunctions, such as cervical insufficiency, uterine prolapse and abnormalities of the uterine cervix. Several genes (e.g., KAZN, PRDM2, PDPN, LRRC28) localised close to the SNP marker on chromosome 12 were grouped in annotation enrichment clusters majorly involved in developmental and biosynthetic pathways, apoptosis, and nucleic acid-templated transcription. Our findings may further contribute to unravel the genomic regions that are important for sheep reproduction and could be incorporated into future selective breeding programmes.
由于对绵羊生产系统有重大影响，绵羊繁殖的遗传结构越来越受到科学界的关注。本研究利用 Illumina Ovine SNP50K BeadChip 进行了基于系谱的分析和全基因组关联研究，以探索高产 Chios 乳用绵羊繁殖的遗传机制。初产年龄、总繁殖力和母羔存活率被选为代表性繁殖性状，估计具有显著的遗传力（h=0.07-0.21），性状之间没有明显的遗传拮抗作用。我们在染色体 2 和 12 上鉴定到与初产年龄相关的新的全基因组和提示性显著单核苷酸多态性（SNP）。在染色体 2 上检测到的新变体跨越 357.79 kb 的区域，具有较高的成对连锁不平衡估计值（r=0.8-0.9）。功能注释分析显示候选基因，如胶原蛋白基因和肌肉生长抑制素基因，参与骨生成、肌肉生成、骨骼和肌肉质量发育，类似于影响排卵率和繁殖力的主要基因的功能。另外的功能富集分析将胶原蛋白基因与多种与子宫相关的功能障碍相关联，如宫颈机能不全、子宫脱垂和子宫颈异常。染色体 12 上靠近 SNP 标记的几个基因（如 KAZN、PRDM2、PDPN、LRRC28）被分组到主要参与发育和生物合成途径、细胞凋亡和核酸模板转录的注释富集簇中。我们的研究结果可能有助于揭示对绵羊繁殖重要的基因组区域，并可能被纳入未来的选择性育种计划。
