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机体生长主要受到促生长激素释放激素—生长激素—胰岛素样生长因子(GHRH-GH-IGFs)生长轴调控,类胰岛素生长因子IGF-Ⅰ是生长激素(GH)发挥生物学功能的重要传导因子。实验特异性扩增了建鲤(Cyprinus carpio var.jian)IGF-Ⅰa基因的5个外显子和3个内含子(内含子1、内含子3和内含子4)。通过比对10尾建鲤的序列,共找到SNPs位点8个。使用PCR-RFLP方法检测了5个家系共372尾建鲤的内含子1_C175G,12个家系共987尾的内含子1_A993G和内含子4_A511C 3个位点。内含子1_C175G雌雄个体均以GG型频率为最高,分别是0.44和0.43;此位点在幼鱼和成鱼时期与雌、雄建鲤增重均无相关性;内含子1_A993G雌雄个体均以AG型频率最高,分别是0.76和0.72;此位点在成鱼阶段与雄性建鲤增重呈显著相关(P<0.05);内含子4_A511C在雌雄个体中均以CC型频率最高,分别是0.48和0.47;其在幼鱼和成鱼阶段均与增重存在极显著的相关性(P<0.01)。本次试验表明在建鲤体内,IGF-I基因在不同生长阶段的表达量不同,且处于同一生长阶段的雌雄个体间的表达也存在差异。内含子1_A993G、内含子4_A511C均与建鲤增重存在相关性,可以考虑作为建鲤分子育种的相关依据。研究亮点:胰岛素样生长因子是一类与生长密切相关的促生长因子。近年来,在鸡、羊、牛等畜禽类动物生长相关分子标记筛选方面已有较多研究并取得一些阳性结果。IGFs多态性及经济性状相关性在鱼类方面报道不多,在鲤方面还没有开展,本文首次自建鲤基因组DNA中分离了IGF-Ⅰa基因,查找了潜在的SNPs位点,并使用可靠的PCR-RFLP方法检测了群体基因型分布,通过与增重的相关分析,筛选到了两个与增重显著相关的SNP位点,为建鲤的分子育种奠定了基础。
Body growth is regulated mainly by the growth axis of the somatotropin-releasing hormone hormone-growth-hormone-insulin-like growth factor (GHRH-GH-IGFs), an important mediator of the biological functions of growth hormone (GH). Five exons and three introns (intron 1, intron 3 and intron 4) of IGF-Ⅰa gene of Cyprinus carpio var. Jian were amplified by PCR. By comparing the sequences of 10 Jian carp, a total of 8 SNPs were found. PCR-RFLP method was used to detect 3 intron 1_C175G of 372 Jian carp and 987 in 12 families of intron 1_A993G and intron 4_A511C in 5 pedigrees. The intron 1_C175G had the highest frequency of GG genotypes in both sexes, which were 0.44 and 0.43, respectively. There was no correlation between GG genotypes and the male and female carp weights during juvenile and adult fish stages. Intron 1_A993G The frequencies of AG genotype were the highest (0.76 and 0.72, respectively). This site was significantly correlated with weight gain of male Jian carp (P <0.05) at adult stage. Intron 4_A511C had the highest frequency of CC genotype in both sexes 0.48 and 0.47 respectively. There was a significant correlation between weight gain and juvenile fish intake (P <0.01). This experiment shows that in Jian carp, the expression of IGF-I gene in different growth stages is different, and the expression of the same growth stage of the male and female individuals are also different. Intron 1_A993G, intron 4_A511C Jian carp weight gain exists, can be considered as Jian carp molecular breeding related basis. Research Highlights: Insulin-like growth factor is a type of growth-promoting factor that is closely related to growth. In recent years, there have been more studies and some positive results in the screening of molecular markers related to the growth of livestock such as chicken, sheep and cattle. The correlation between IGFs polymorphism and economic traits has not been reported in fish and has not been carried out in common carp. In this paper, IGF-Ⅰa gene was isolated from genomic DNA of self-built common carp for the first time, and the potential SNPs were found and used as reliable PCR-RFLP method was used to detect the distribution of population genotypes. Through correlation analysis with weight gain, two SNPs significantly associated with weight gain were screened, which laid the foundation for the molecular breeding of Jian carp.