湖羊NR5A1基因SNPs筛选及其与产羔数的关联分析

SNPs selection of NR5A1 and its association analysis with litter size in Hu sheep

为探讨NR5A1基因能否作为湖羊产羔性状的候选基因,同时寻找与湖羊繁殖性能相关的分子标记,以高繁殖力湖羊为研究对象,采用DNA池结合测序方法筛选NR5A1基因在湖羊中的SNPs位点,并利用PCR-RFLP和AS-PCR方法进行多态位点分型,利用SPSS软件分析不同基因型与湖羊产羔数的相关性。结果表明,在湖羊NR5A1基因中检测到6个SNPs位点,分析发现g.6052A/G位点为Taq I酶切位点,其余5个位点处没有酶切位点存在。在湖羊群体中,g.3362G/C(GG、GC、CC)、g.4342G/A(GG、GA、AA)、g.4666C/T(CC、CT、TT)、g.6052A/G(GG、AG、AA)和g.6991T/G(TT、TG、GG)位点均检测到3种基因型,而g.5699C/G位点在湖羊群体中仅发现2种基因型GG和GC。6个位点的多态信息含量(PIC)从0.306到0.375不等,均属于中度多态(0.25<PIC<0.50),杂合度(He)从0.377到0.500,在这6个SNPs位点中,仅g.6052A/G位点处于Hardy-Weinberg平衡状态。连锁分析发现,g.3362G/C和g.6052A/G 2位点在湖羊群体中紧密连锁,二者共构建了8种单倍型组合,AAGG为主要的单倍型,占总数的35.90%,AGCG和AACG次之,分别占总数的20.30%和18.75%。关联分析发现g.6052A/G位点GG型湖羊的平均产羔数显著高于AA型(P<0.05)和AG型(P<0.05),其余位点的各基因型在湖羊的头胎产羔数、二胎产羔数、三胎产羔数和平均产羔数间差异均不显著。AAGG单倍型和AACG单倍型的二胎产羔数比AGCG单倍型的二胎产羔数分别多0.40(P<0.05)和0.53(P<0.01),差异显著。说明,NR5A1基因对湖羊产羔数有一定的影响,g.6052A/G位点、g.3362 G/C和g.6052A/G连锁可作为湖羊繁殖性能的有效遗传标记,用于湖羊的分子选育。

In order to explore whether NS5Ai gene can be used as a candidate gene of the litter size of Hu sheep,SNPs were screened and the correlation between dif-ferent genotypes and litter size of Hu sheep were analyzed.High fecundity sheep were used as the research objective, the SNPs of NR5A1 gene was screened using DNA pools combining with sequencing, and the correlations between different genotypes and litter size of Hu sheep were ana-lyzed using SPSS software. Six SNPs locus were detected in Hu sheep population. g.6052A/G locus owned the TaqI enzyme site and other five SNPs were absent enzyme sites. In Hu sheep population, there were three genotypes in the loci of g.3362G/G（CC, CT ,GC, CC）, g.4342G/A （GG,GA , AA） , g. 4666C/T（CC, CT, TT） ,g.6052A/G （GG, AG, AA） and g.6991T/G （TT, TG, GG） and only two genotypes in g.5699C/G （GG, GC） locus. The PIC of these six SNPs ranged from 0.306 to 0.375 and belonged to moderate polymor-phism （0.25〈PIC〈0.50） , the He ranged from 0.377 to 0.500, and only g.6052A/G locus was in Hardy-Weinberg equilib-rium. Linkage analysis results show-ed that the locus of g.3362 G/C and g.6052A/G were close linkage, and they construc-ted eight haplotypes, among them, AAGG was the main haplotype counting for 35.90% of the total, follow-ed by AGCG and AACG haplotypes counting for 20.30% and 18.75% of the total, respectively. Correlation analysis results showed that the average litter size of ewes with GG genotype at g. 6052A/G locus were significant higher than that of AA and AG （ P〈0.05） , and there were no significant difference in litter sizes among other genotypes of other five loci. The ewes with AAGGand AACG haplotypes have 0.40 （ P〈0.05） and 0.53 （ P〈0.01） litter size more than that with AGCG haplotype in the sec-ond birth, and the difference was very significant. The results showed that NR5A1 gene has certain influence to the littersize of Hu sheep, the single locus of g.6052A/G and the linkage of g.3362 G/C and g.6052A/G can be used as effective ge-netic markers in molecular breed of Hu sheep.