Carcangiu V, Luridiana S, Pulinas L, Di Stefano M V, Cosso G, Mura M C
Department of Veterinary Medicine, Sassari University, Via Vienna 2, 07100, Sassari, Italy.
Heliyon. 2021 Mar 15;7(3):e06489. doi: 10.1016/j.heliyon.2021.e06489. eCollection 2021 Mar.
This research has two aims: (i) to characterize the coding sequence of the gene in dairy sheep in order to investigate possible relationships between single nucleotide polymorphisms (SNPs) and milk traits; and (ii) to investigate possible relationship between gene expression and nucleotide variation. Four hundred adult and multiparous lactating Sarda breed ewes were selected from two farms. Milk samples were collected from Day 30 to Day 150 of lactation to determine the mean yield, somatic cell count, lactose, fat, and protein content of the milk. RNA was extracted from the milk samples, after which the gene coding regions were amplified and sequenced to scan mutations. Whilst eight SNPs were identified, none had statistically significant association with the analysed milk traits. Moreover, the identified expression patterns were not affected by the SNP or combined genotypes. High gene expression levels were found to be correlated with high milk fat content ( < 0.01), indicating the crucial role of this gene in the milk fat synthesis. In conclusion, the polymorphisms found within SREBP-1 gene exhibited no significant associations with milk traits or with individual SREBP-1 mRNA expression patterns. The findings thus suggest that this small genetic variability may derive from the selection carried out in Sarda breed to improve milk yield.
（i）对奶羊中该基因的编码序列进行特征分析，以研究单核苷酸多态性（SNP）与乳性状之间的可能关系；（ii）研究该基因表达与核苷酸变异之间的可能关系。从两个农场选取了400只成年经产泌乳的撒丁岛品种母羊。在泌乳第30天至第150天采集乳样，以测定乳的平均产量、体细胞计数、乳糖、脂肪和蛋白质含量。从乳样中提取RNA，之后扩增并测序该基因的编码区以扫描突变。虽然鉴定出了8个SNP，但没有一个与所分析的乳性状具有统计学上的显著关联。此外，所鉴定的表达模式不受SNP或组合基因型的影响。发现该基因的高表达水平与高乳脂肪含量相关（<0.01），表明该基因在乳脂肪合成中起关键作用。总之，在SREBP-1基因内发现的多态性与乳性状或个体SREBP-1 mRNA表达模式均无显著关联。因此，这些发现表明这种微小的遗传变异性可能源于撒丁岛品种为提高产奶量而进行的选择。
