【摘要】 促生长激素释放激素(growth hormone-releasing hormone, GHRH)是调控生长激素释放的重要因子。为探索GHRH基因多态性对草鱼(Ctenopharyngodon idella)生长性状的影响,本研究采用PCR扩增得到GHRH基因的cDNA和DNA全序列(GenBank No. 2446387),其中cDNA序列全长为602 bp,DNA序列长为5 244 bp,包含5个外显子和4个内含子。通过直接测序法在该基因上筛选到12个SNP,分别位于核苷酸序列中的第670、1 798、2 340、2 782、3 925、4 227、4 371、4 420、4 497、4 976、5 025和5 232 bp处。采用SNaPshot技术对12个SNP标记进行基因分型,经一般线性模型分析SNP标记与性状相关性,结果显示,T+3925C、G+4227A、T+4420A、C+4497T、A+4976G和G+5025T标记完全连锁,组成单倍型标记D1,4个标记与草鱼生长性状存在显著相关性(P<0.05),分别是C+1798T、T+2340C、A+2782T和单倍型D1标记,其中C+1798T标记的CC基因型个体的体质量性状均值显著高于TT基因型个体(P<0.05)。T+2340C标记TT基因型的体质量、体长、体高和头长的性状均值显著高于CT基因型个体(P<0.05)。A+2782T标记的AA基因型个体的体质量和体长性状均值显著高于其他两种基因型个体(P<0.05)。单倍型D1标记的EE基因型(TTGGTTCCAAGG)体质量性状均值显著高于其他两种基因型个体(P<0.05)。对4个标记进行连锁不平衡分析发现,其两两组合间均处于强连锁不平衡状态(D’>0.8),具有6种单倍型分别为H1(CTAE)、H2 (TTTF)、H3 (CTTF)、H4 (CTTE)、H5 (CCTE)和H6 (TTAE)。单倍型组合H1/H1 (CCTTAAEE)个体的体质量极显著性地高于除H1/H3个体之外的其他单倍型组合(P<0.01),且比群体平均体质量高9.96%。本研究获得标记C+1798T、T+2340C、A+2782T、单倍型D1标记和单倍型组合H1/H1均与生长性状显著相关,为草鱼分子标记辅助育种提供了候选标记,可加快草鱼良种选育进程。更多还原

【Abstract】 Growth hormone-releasing hormone(GHRH) plays an important role in regulating the release of growth hormone in animals. In order to study the relationship between the GHRH gene polymorphism and growth traits in grass carp(Ctenopharyngodon idella), the c DNA and DNA sequence of GHRH gene(GenBank No. 2446387) were obtained by PCR amplification. Total length of c DNA and DNA sequence of GHRH were602 and 5 244 bp, respectively, including 5 exons and 4 introns. Through direct sequencing, 12 SNP were identified in the DNA sequence, which located at 670, 1 798, 2 340, 2 782, 3 925, 4 227, 4 371, 4 420, 4 497, 4976, 5 025 and 5 232 bp, respectively. After analysis with SNaPshot technique and General linear model, T+3925 C, G+4227 A, T+4420 A, C+4497 T, A+4976 G and G+5025 T were linked to form haplotype marker D1,and 4 SNPs were shown to have significant correlation with the growth traits in grass carp, which were C+1798 T, T+2340 C, A+2782 T and haplotype D1 marker, respectively. The body weight in individuals with CC genotype in C+1798 T was significantly higher than TT genotype(P<0.05); the body weight, body length,body height and head length in individuals with TT genotype in T+2340 C were significantly higher than CT genotype(P<0.05); the body weight and body length in individuals with AA genotype in A+2782 T were significantly higher than the other 2 genotypes(P<0.05); the body weight in individuals with EE genotype in haplotype D1(TTGGTTCCAAGG) were significantly higher than the other 2 genotype(P<0.05). The linkage disequilibrium analysis of the 4 markers showed that the 2 combinations were in a strong linkage disequilibrium state(D’>0.8), which included 6 haplotypes: H1(CTAE), H2(TTTF), H3 CTTF), H4(CTTE),H5(CCTE) and H6(TTAE). The body weight in haplotype combination of H1/H1(CCTTAAEE) was significantly higher than that of other haplotype combinations(except H1/H3, P<0.01), which was 9.96%higher than the average body weight of the population. In conclusion, C+1798 T, T+2340 C, A+2782 T,haplotype D1 markers and haplotype combination H1/H1 in GHRH were significantly correlated with growth traits, which provides candidate markers for marker assisted breeding in grass carp, and contributes to accelerate the breeding process of grass carp.更多还原