FADS2基因c.1571A>G突變對中國荷斯坦牛泌乳性狀的影響

王夢琦 倪煒 唐程

摘要 [目的]探索FADS2基因 c.1571 A>G多態(tài)性對中國荷斯坦牛泌乳性狀的影響。[方法]對866頭中國荷斯坦牛FADS2基因c.1571 A>G位點進行多態(tài)性分析，采用最小二乘法分析其對泌乳性狀的影響。[結(jié)果]FADS2 c.1571 A>G 對日產(chǎn)奶量、乳蛋白率、乳脂率、總固形物以及尿素氮含量等泌乳性狀有顯著影響（P<0.05）。GG基因型個體具有較高的日產(chǎn)奶量，而AA型個體的乳脂率、乳蛋白率及總固形物含量顯著高于其他基因型個體。 FADS2 c.1571 A>G突變對體細(xì)胞評分（SCS）無顯著影響（P>0.05）。[結(jié)論]FADS2可作為優(yōu)化中國荷斯坦牛泌乳性能的潛在分子標(biāo)記。

關(guān)鍵詞 FADS2;c.1571 A>G;體細(xì)胞評分;泌乳性狀

中圖分類號 S813.1文獻標(biāo)識碼 A

文章編號 0517-6611（2019）10-0092-02

Abstract [Objective]To explore the effects of c.1571 A>G polymorphism of FADS2 gene on the lactation traits of Chinese Holstein cows.[Method] The single nucleotide polymorphisms （SNPs） of c.1571 A>G mutation of FADS2 gene in Chinese Holstein cows （n=866） were analyzed，and their effects on the lactation traits of Chinese Holstein cows were analyzed by using least square method.[Result] c.1571 A>G mutation of FADS2 gene had significant effects on daily milk yield，milk protein content，milk fat content，total solids and urea nitrogen content，and other milk production traits （P<0.05）. The individuals with GG genotype had significantly higher daily milk yield，while the individuals with AA genotype had significantly higher milk fat content，milk protein content and content of total solids.FADS2 c.1571 A>G mutation had no significant effect on SCS.[Conclusion] FADS2 could be used as the potential molecular markers for improving the? lactation performance of Chinese Holstein cows.

Key words FADS2;c.1571 A>G mutation;Somatic cell score（SCS）;Lactation traits

泌乳性狀是奶牛長期選擇育種所依據(jù)的主要經(jīng)濟性狀，如日產(chǎn)奶量、乳脂率、乳蛋白率、乳糖含量、總固形物和乳中尿素氮等[1]。經(jīng)濟性狀通常受多基因的調(diào)控，因此探索對這些性狀有較大影響的基因尤為重要[2]。然而，目前只發(fā)現(xiàn)少數(shù)的突變與牛奶組成相關(guān)[3]。

脂肪酸去飽和酶（fatty acid desaturases，F(xiàn)ADS）是脫氫酶家族的成員，通過脫氫作用在脂肪酸鏈特定位置上催化C-C 轉(zhuǎn)換成C=C[4]，對脂肪酸向多不飽和脂肪酸的轉(zhuǎn)化起催化作用。FADS1和FADS2基因調(diào)控多不飽和脂肪酸代謝路徑并影響血漿中的多不飽和脂肪酸含量[5]。Matsumoto等[6]發(fā)現(xiàn)FADS2 g.-823G>A 對牛肉品質(zhì)評分有顯著影響。IbeaghaAwemu 等[7]報道了加拿大荷斯坦牛FADS2基因的33個SNPs，并發(fā)現(xiàn)FADS2基因3 非轉(zhuǎn)錄區(qū)域（3 untranscript region，3UTR）c.1571 A>G 和 c.2776 A>G 與牛奶中多不飽和脂肪酸含量顯著相關(guān)。 Fatima等[8]報道產(chǎn)后奶牛處于能量負(fù)平衡時FADS2基因表達下調(diào)。以上研究表明FADS2與泌乳性狀有潛在影響，但FADS2與泌乳性狀（如產(chǎn)奶量、乳脂率以及乳蛋白率等）的關(guān)系并不確定。筆者探討了FADS2基因c.1571 A>G突變對中國荷斯坦牛泌乳性狀的潛在影響。

1 材料與方法

1.1 試驗動物與泌乳性狀收集

從江蘇省某大型荷斯坦牛奶牛場采集866頭中國荷斯坦泌乳奶牛血液樣本，用于提取DNA。同時，采集2013年6月至2016年12月DHI生產(chǎn)記錄，共來自866頭奶牛2 198個泌乳周期的20 532條測定日生產(chǎn)記錄用于表性分析，性狀主要包括日產(chǎn)奶量、乳脂率、乳蛋白率、脂蛋白比、體細(xì)胞數(shù)、SCS、乳糖、總固體和尿素氮。

1.2 DNA 提取、SNP 分型以及miRNA 結(jié)合位點預(yù)測

采用標(biāo)準(zhǔn)的苯酚-氯仿法從中國荷斯坦牛血液中提取DNA[9]。根據(jù)FADS2基因序列（BC123735.1），采用飛行時間質(zhì)譜法檢測FADS2基因3UTR區(qū)c.1571 A>G SNP突變。使用Target Scan7.0軟件預(yù)測變異位點結(jié)合的miRNA。

[4] MANGRAVITE L M，DAWSON K，DAVIS R R，et al.Fatty acid desaturase regulation in adipose tissue by dietary composition is independent of weight loss and is correlated with the plasma triacylglycerol response[J].The American journal of clinical nutrition，2007，86（3）：759-767.

[5] MERINO D M，MA D W L，MUTCH D M.Genetic variation in lipid desaturases and its impact on the development of human disease[J].Lipids in health and disease，2010，9（1）：1-14.

[6] MATSUMOTO H，NOGI T，TABUCHI I，et al.The SNPs in the promoter regions of the bovine FADS2 and FABP4 genes are associated with beef quality traits[J].Livestock science，2014，163：34-40.

[7] IBEAGHAAWEMU E M，AKWANJI K A，BEAUDOIN F，et al.Associations between variants of FADS genes and omega3 and omega6 milk fatty acids of Canadian Holstein cows[J].BMC Genetics，2014，15（1）：1-9.

[8] FATIMA A，WATERS S，O′BOYLE P，et al.Alterations in hepatic miRNA expression during negative energy balance in postpartum dairy cattle[J].BMC Genomics，2014，15（1）：1-10.

[9] WINFREY M R，ROTT M A，WORTMAN A T.UnraVeling DNA：Molecular biology for the laboratory[M].New York： PrenticeHal，199.

[10] SHI Y Y，HE L.SHEsis， a powerful software platform for analyses of linkage disequilibrium， haplotype construction， and genetic association at polymorphism loci[J].Cell research，2005，15（2）：97-98.

[11] LAROCHELLE J R，F(xiàn)ODOR M，XU X，et al.Structural and functional consequences of three cancerassociated mutations of the oncogenic phosphatase SHP2[J].Biochemistry，2016，55（15）：2269-2277.

[12] DANDREA S，GUILLOU H，JAN S，et al.The same rat Δ6desaturase not only acts on 18but also on 24carbon fatty acids in verylongchain polyunsaturated fatty acid biosynthesis[J].Biochemical journal，2002，364（1）：49-55.

[13] GRECO L，NETO J T N，PEDRICO A，et al.Effects of altering the ratio of dietary n6 to n3 fatty acids on performance and inflammatory responses to a lipopolysaccharide challenge in lactating Holstein cows[J].Journal of dairy science，2015，98（1）：602-617.

[14] YOUNGERMAN S，SAXTON A M，OLIVER S P，et al.Association of CXCR2 polymorphisms with subclinical and clinical mastitis in dairy cattle[J].Journal of dairy science，2004，87（8）：2442-2448.