Department of Animal Science, College of Agriculture, Food and Climate Science, Injibara University, Injibara, Ethiopia.
Animal Genetics and Breeding Division, ICAR -National Dairy Research Institute, Karnal, India.
BMC Genom Data. 2024 Mar 18;25(1):32. doi: 10.1186/s12863-024-01209-x.
The genetic progress of fertility and reproduction traits in dairy cattle has been constrained by the low heritability of these traits. Identifying candidate genes and variants associated with fertility and reproduction could enhance the accuracy of genetic selection and expedite breeding process of dairy cattle with low-heritability traits. While the bovine LAP3 and SIRT1 genes exhibit well-documented associations with milk production traits in dairy cattle, their effect on cow fertility have not yet been explored. Eleven single nucleotide polymorphisms (SNPs), comprising five in the promoter (rs717156555: C > G, rs720373055: T > C, rs516876447: A > G, rs461857269: C > T and rs720349928: G > A), two in 5'UTR (rs722359733: C > T and rs462932574: T > G), two in intron 12 (rs110932626: A > G and rs43702363: C > T), and one in 3'UTR of exon 13 (rs41255599: C > T) in LAP3 and one in SIRT1 (rs718329990:T > C) genes, have previously been reported to be associated with various traits of milk production and clinical mastitis in Sahiwal and Karan Fries dairy cattle. In this study, the analysis primarily aimed to assess the impact of SNPs within LAP3 and SIRT1 genes on fertility traits in Sahiwal and Karan Fries cattle. Association studies were conducted using mixed linear models, involving 125 Sahiwal and 138 Karan Fries animals in each breed. The analysis utilized a designated PCR-RFLP panel.
In the promoter region of the LAP3 gene, all variants demonstrated significant (P < 0.05) associations with AFC, except for rs722359733: C > T. However, specific variants with the LAP3 gene's promoter region, namely rs722359733: C > T, rs110932626: A > G, rs43702363: C > T, and rs41255599: C > T, showed significant associations with CI and DO in Sahiwal and Karan Fries cows, respectively. The SNP rs718329990: T > C in the promoter region of SIRT1 gene exhibited a significant association with CI and DO in Sahiwal cattle. Haplotype-based association analysis revealed significant associations between haplotype combinations and AFC, CI and DO in the studied dairy cattle population. Animals with H2H3 and H2H4 haplotype combination exhibited higher AFC, CI and DO than other combinations.
These results affirm the involvement of the LAP3 and SIRT1 genes in female fertility traits, indicating that polymorphisms within these genes are linked to the studied traits. Overall, the significant SNPs and haplotypes identified in this study could have the potential to enhance herd profitability and ensure long-term sustainability on dairy farms by enabling the selection of animals with early age first calving and enhance reproductive performance in the dairy cattle breeding program.
奶牛繁殖和生育性状的遗传进展受到这些性状低遗传力的限制。鉴定与繁殖和生育相关的候选基因和变体可以提高遗传选择的准确性，并加速具有低遗传力性状的奶牛的选育过程。虽然牛 LAP3 和 SIRT1 基因与奶牛产奶性状具有良好的相关性，但它们对奶牛生育力的影响尚未得到探索。11 个单核苷酸多态性（SNP），包括启动子中的 5 个（rs717156555：C > G、rs720373055：T > C、rs516876447：A > G、rs461857269：C > T 和 rs720349928：G > A）、5'UTR 中的 2 个（rs722359733：C > T 和 rs462932574：T > G）、内含子 12 中的 2 个（rs110932626：A > G 和 rs43702363：C > T）和 1 个外显子 13 中的 3'UTR 中的 1 个（rs41255599：C > T）在 LAP3 和 1 个 SIRT1 基因（rs718329990：T > C）中，先前已被报道与 Sahiwal 和 Karan Fries 奶牛的产奶和临床乳腺炎的各种性状有关。在这项研究中，分析的主要目的是评估 LAP3 和 SIRT1 基因内的 SNP 对 Sahiwal 和 Karan Fries 牛的繁殖性状的影响。使用混合线性模型进行关联研究，每个品种涉及 125 头 Sahiwal 和 138 头 Karan Fries 动物。分析利用了一个指定的 PCR-RFLP 小组。
在 LAP3 基因的启动子区域，所有变体都与 AFC 显著相关（P < 0.05），除了 rs722359733：C > T。然而，特定的变体与 LAP3 基因的启动子区域，即 rs722359733：C > T、rs110932626：A > G、rs43702363：C > T 和 rs41255599：C > T，分别与 Sahiwal 和 Karan Fries 奶牛的 CI 和 DO 显著相关。SIRT1 基因启动子区域的 SNP rs718329990：T > C 与 Sahiwal 牛的 CI 和 DO 显著相关。基于单倍型的关联分析显示，研究奶牛群体中，单倍型组合与 AFC、CI 和 DO 之间存在显著关联。与其他组合相比，H2H3 和 H2H4 单倍型组合的动物具有更高的 AFC、CI 和 DO。
这些结果证实了 LAP3 和 SIRT1 基因参与了雌性生育性状，表明这些基因内的多态性与研究的性状有关。总的来说，本研究中鉴定的显著 SNP 和单倍型可能具有提高牛群盈利能力和确保奶牛养殖计划长期可持续性的潜力，方法是选择具有早期首次产犊和提高繁殖性能的动物。
