三个牛品种MBL1基因第一内含子与第二外显子遗传多态性研究

Studies on Polymorphisms Within Intron 1 and Exon 2 of MBL1 Gene in Three Cattle Breeds

采用巢式PCR、DNA测序和CRS-PCR方法,研究中国荷斯坦牛、鲁西黄牛、渤海黑牛的MBL1基因内含子1和外显子2的单核苷酸多态性(SNPs),发现了855(G/A)、2651(G/A)和2686(T/C)3个新SNP位点。855(G/A)位于内含子1上,2651(G/A)导致Val24 Ile氨基酸的改变,2686(T/C)为同义突变。3个SNP位点在3个牛品种群体中优势等位基因相同,分别为G、G、C,其等位基因频率分别为0.87/0.58/0.57、1/0.75/0.74、1/0.76/0.63。经χ2适合性检验,荷斯坦牛在855(G/A)位点、鲁西黄牛在855(G/A)、2651(G/A)位点、渤海黑牛的所有位点达到Hardy-W e inberg平衡状态(P>0.05)。3个牛品种在855(G/A)位点均表现为低度多态;在2651(G/A)和2686(T/C)位点均表现为中度多态(0.25<PIC<0.5)。

The single nucleotide polymorphisms（SNPs） within intron 1 and exon 2 of MBL1 gene in Chinese Holstein,Luxi cattle and Bohai cattle were investigated by using nested-PCR,DNA sequencing technology and CRS-PCR method.Sequencing results showed that three new SNPs were identified.They were 855（G/A）、2651（G/A） and 2686（T/C）.855（G/A）SNP was located in intron 1;2651（G/A）caused amino acids alteration in Val24Ile;2686（T/C）was synonymous mutation.Predominant allele were identical at three SNP sites in three cattle populations,which were G,G,C and the allelic frequencies were 0.87/0.58/0.57,1/0.75/0.74,1/0.76/0.63,respectively.By χ2 tests,we found that 855（G/A） of Chinese Holstein,855（G/A） and 2651（G/A） of Luxi cattle and all sites of Bohai cattle were in accordance with Hardy-Weinberg equilibrium（P〉0.05）.The value of polymorphism information indicated that 855（G/A） was slight polymorphism;2651（G/A）and 2686（T/C）were moderate polymorphism in the three cattle breeds（0.25〈PIC〈0.5）.