中国农业科学 ›› 2016, Vol. 49 ›› Issue (11): 2194-2202.doi: 10.3864/j.issn.0578-1752.2016.11.015

• 畜牧·兽医·资源昆虫 • 上一篇    下一篇

中国荷斯坦牛FADS2基因3′端SNP突变对乳中脂肪酸组成的影响

徐晨希,王梦琦,朱小瑞,张玉锋,夏海磊,刘贤慧,王小龙,张慧敏,杨章平,毛永江   

  1. 扬州大学动物科学与技术学院,江苏扬州 225009
  • 收稿日期:2015-10-28 出版日期:2016-06-01 发布日期:2016-06-01
  • 通讯作者: 毛永江,E-mail:cattle@yzu.edu.cn
  • 作者简介:徐晨希, E-mail:chouchouxcx@163.com。王梦琦,E-mail:770406499@qq.com。徐晨希和王梦琦为同等贡献作者。
  • 基金资助:
    国家自然科学基金(31272407, 31372286,31472067)、江苏省优势学科(PAPD)、国家级大学生创新训练计划(201411117031)、江苏省大学生实践创新训练计划(201411117031Z)

Effects of SNPs in the 3’ Untranslated Regions of FADS2 on the Composition of Fatty Acids in Milk of Chinese Holstein

XU Chen-xi, WANG Meng-qi, ZHU Xiao-rui, ZHANG Yu-feng, XIA Hai-lei, LIU Xian-hui, WANG Xiao-long, ZHANG Hui-min, YANG Zhang-ping, MAO Yong-jiang   

  1. College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, Jiangsu
  • Received:2015-10-28 Online:2016-06-01 Published:2016-06-01

摘要: 【目的】FADS2是多不饱和脂肪酸合成中关键的限速酶之一,可催化食物中亚油酸(LNA, C18:2n6)合成γ-亚麻酸(GLA, C18:3n6)、二十碳五烯酸(EPA, C20:5n3)、二十二碳六烯酸(DHA, C22:6n3)等长链脂肪酸。试验旨在探讨中国荷斯坦牛FADS2基因3′端非编码区SNP突变对乳中脂肪酸含量的影响。【方法】随机选择20头无亲缘关系的中国荷斯坦牛样本,用直接测序列法检测FADS2基因3′端非编码区SNP突变位点。再以江苏某大型奶牛场551头中国荷斯坦牛为材料,用飞行时间质谱法对前期发现的2个SNP位点进行检测,同时利用最小二乘模型分析了SNP突变及其单倍型对乳中脂肪酸含量及其不饱和指数的影响。【结果】 中国荷斯坦牛FADS2基因3′端非编码区存在3个SNP突变位点:c.1571 A>G、c.2743 A>G、c.2776 A>G。c.1571 A>G位点GG型为优势基因型,基因型频率为0.800,G为优势等位基因,基因频率为0.887。c.2776 A>G位点AA为优势基因型,基因型频率为0.673,A为优势等位基因,基因频率为0.819。χ2 检验表明:c.2776 A>G位点基因型分布均符合Hardy-Weinberg 平衡(P>0.05) ,而c.1571 A>G位点基因型分布均偏离Hardy-Weinberg 平衡(P<0.05)。FADS2基因c.1571 A>G位点与c.2776 A>G位点间连锁不平衡系数r2为0.028,未达到显著水平(P>0.05)。c.1571 A>G位点与c.2776 A>G位点有3种单倍型,GA、GG和AA频率分别为0.705、0.181和0.114。多因素方差分析表明:FADS2-1571对C14:1含量、C14和C18不饱和指数的影响达到极显著水平(P<0.01),对C18:0、SFA和MUFA含量的影响达到显著水平(P<0.05)。GG型个体乳中C14:1含量、C14和C18不饱和指数显著高于AG型(P<0.05)。FADS2-2776位点对C16:1含量、 C16和C20不饱和指数的影响达到极显著水平(P<0.01),对C14:1含量的影响达到显著水平(P<0.05),GG型个体乳中C16:1含量、C16和C20不饱和指数显著高于AG型和AA型(P<0.05)。同时,FDAS2-1571-2776单倍型对C16:1含量和C20不饱和指数的影响达到显著水平(P<0.05),单倍型GG型个体乳中C16:1含量和C20不饱和指数显著高于GA型和AA型(P<0.05)。【结论】FADS2基因3′端非编码区SNP突变对中国荷斯坦牛乳中脂肪酸组成有重要影响。在进一步验证其功能情况下,可作为影响中国荷斯坦奶牛乳脂肪酸组成的主效基因加以利用。

关键词: 中国荷斯坦牛, FADS2, SNPs, 脂肪酸组成

Abstract: 【Objective】D-6-fatty acid desaturase 2 (FADS2) is one of the key limiting enzymes in the conversion of dietary essential 18 carbon PUFAs (18C-PUFAs) such as linoleic acid (LNA,C18:2n-6) to γ-linolenic acid (GLA, 18:3n6), eicosapentaenoic acid (EPA, C20:5n3) and docosahexaenoic acid (DHA, C22:6n3). The objective of this study was to investigate the effects of SNPs in the 3’ untranslated regions of FADS2 gene on the compositions of fatty acids in milk of Chinese Holstein.【Method】In this study, 20 Chinese Holstein cows were selected randomly for PCR amplification and sequencing of the 3’ untranslated regions of FADS2 gene used for SNP discovery. Then the Chinese Holstein cows (n =551) were genotyped using Sequenom MassARRAY (Sequenom Inc., San Diego, CA) based on the previous SNP information in this study, and the associations between SNPs or haplotypes and compositions of fatty acids, unsaturated indexes of fatty acids in milk were analyzed by the least squares method in the GLM procedure of SPSS.【Result】Three SNPs (c.1571 A>G, c.2743 A>G and c.2776 A>G) were identified in the 3’ untranslated regions of FADS2 gene. The genotype GG was the dominant genotype, which the frequencies were 0.800 for c.1571 A>G, allele G was dominant allele with the frequency of 0.887. The genotype AA was the dominant genotype, which the frequencies were 0.673 for c. 2776 A>G. The allele A was dominant allele with the frequency of 0.819. The coefficient of disequilibrium was 0.028 between c.1571 A>G and c.2776 A>G, which was not significant at P<0.05. There were 3 haplotypes for FADS2 c.1571 A>G and c.2776 A>G, which the frequencies were 0.705, 0.181 and 0.114 for GA, GG and AA, respectively. χ2 test indicated that the c.2776 A>G fitted with Hardy-Weinberg equilibrium in the population (P>0.05), and the c.1571 A>G deviated from Hardy-Weinberg equilibrium (P<0.05). The SNP c.1571 A>G showed a very significant association with C14:1, unsaturated indexes of C14 and C18 (P<0.01), and significant association with C18:0, SFA and MUFA (P<0.05). The individuals with genotype GG had higher C14:1, unsaturated indexes of C14 and C18 than genotypes AG (P<0.05). The SNP c.2776 A>G showed a very significant association with C16:1, unsaturated indexes of C16 and C20 (P<0.01), and significant association with C14:1 (P<0.05). The individuals with genotype GG had higher C16:1, unsaturated indexes of C16 and C20 than genotypes AG and AA (P<0.05). In the meantime, the haplotype of FADS2 1571-2776 showed a significant association with C16:1, unsaturated indexes of C20 (P<0.05). The individuals with genotype GG had higher C16:1, unsaturated indexes of C20 than genotypes GA and AA (P<0.05). 【Conclusion】The SNPs in the 3’ untranslated regions of FADS2 gene have significant genetic effects on composition of fatty acids in milk, but further investigation will be required to elucidate the biological and practical relevance of these SNPs.

Key words: Chinese Holstein, FADS2, SNPs, composition of fatty acids