草鱼醛缩酶B基因部分序列的SNP多态性及其与生长性状的关联分析

Polymorohisms of SNPs in ALDO B gene and association analysis with growth traits in grass carp(Ctenopharyngodon idellus)

通过佛山市白金水产良种选育场提供的草鱼EST库的醛缩酶B基因重叠群的2个Contig扩增该基因的序列片段,采用直接测序法,经过序列比对,共筛到C+687G、C+1042A和A117C等3个颠换SNPs位点。C+687G位于醛缩酶B基因外显子6的63 bp处,为同义突变;C+1042A位于外显子8的43 bp处,为错义突变;A117C位于内含子7的117 bp处。采用Snapshot方法对同一群体的296尾草鱼的这3个SNPs位点进行检测和分型,并统计基因型频率。3个SNPs位点中AA的频率分别为42.9%、32.8%、32.8%;AB的频率分别为42.9%、45.9%、45.6%;BB的频率分别为14.2%、21.3%、21.6%。利用一般线性模型分析3个SNPs位点与草鱼体质量、体长等重要生长性状的关系,关联分析结果显示,C+687G位点不同基因型只在体长/尾柄长比值上存在显著差异(P<0.05),和体质量等重要生长性状不相关。A117C和C+1042A两个位点都在体质量等4个生长性状上存在显著差异(P<0.05)。将3个SNPs位点不同基因型两两位点组成3个组合的双倍型(都去掉了频率小于3%的组合),结果显示,C+687G和A117C以及C+687G和C+1042A的2个组合分别组成的7种双倍型在体质量等5个生长性状上都存在显著差异(P<0.05);A117C和C+1042A组成的3种双倍型在体质量、眼间距等2个生长性状上都存在显著差异(P<0.05)。研究认为,可以考虑将草鱼醛缩酶B基因作为生长相关的候选基因,用于草鱼的分子辅助育种。

Aldolase is a glycolytic enzyme,which plays a key and pivotal role in glycolysis and glucose metabolism.And compared to aldolase A and aldolase C,aldolase B is involved in both glycolysis and gluconeogenesis.In this research,the two genomic sequence fragments are amplified according to two contigs cDNA fragments of ALDOB gene from EST database of grass carp（Ctenopharyngodon idellus）.Then three nucleotides mutations were identified by using directly sequencing and blasting.The polymor-phisms are C＋687G,A117C and C＋1042A,which are in exon 6,intron 7 and exon 8 respectively.C＋687G is synonymous mutation and-A63C is non-synonymous mutation.296 grass carps were used to genotype polymorphisms and then calculate the genotype and gene frequency by SnaPshot method.Frequencies of the AA genotype were 42.9%,32.8% and 32.8% respectively,the AB genotype were 42.9%,45.9% and 45.6% respectively,the BB genotype were 14.2%,21.3% and 21.6% respectively.A general linear model was used to statistically analyze the relationship between ALDOB gene polymorphisms and major growth traits.The result indicated that the three different genotypes of C＋687G site only showed significant association at body length/caudal peduncle ratio（P〈0.05）,while they showed no significant association at body weight.The three different genotypes of A117C andC＋1042A sites showed significant association at body weight and so on（P〈0.05）.Three combinations of seven,three and seven diplotypes,with the minor allelic frequencies of above 3%,were constructed based on three SNPs in the experiment population.As-sociation analysis indicated that three combinations of diplotypes were all significant association between diplotypes and body weight（P〈0.05）： the seven diplotypes of C＋687G,A117C and C＋687G,C＋1042A showed significant association at body weight,body width and so on（P〈0.05）.And the three diplotypes of A117C and-43C,C＋1042A showed significant association at body weight and space.Not only different genotypes of three SNPs sites,but also diplotypes showed significant association in major growth traits in grass carp.And the homozygous genotypes were higher than heterozygote genotypes in the main growth traits.As a result,ALDO B gene could be a candidate modifier gene for grass carp growth traits which could be useful for grass carp molecular breeding.