鳜胃蛋白酶基因外显子7上SNP检测及其与食性驯化相关分析

Association of polymorphism detection of SNPs in exon 7 of pepsino-gen(PEP) and feeding behavior domestication in Siniperca chuatsi

本研究旨在探寻胃蛋白酶(pepsinogen,PEP)基因的等位基因及其基因型在不同食性驯化表型鳜(Siniperca chuatsi)群体中的分布情况。通过2周食性驯化,挑选出最易驯化和最不易驯化的2组,提取各组鳜鳍条组织DNA,采用PCR产物直接测序法(direct sequencing,DS)、限制性片段长度多态性技术(restriction fragment length poly-morphism,RFLP)和创造限制酶切位点PCR法(created restriction site PCR,CRS-PCR)对鳜胃蛋白酶基因5、6、7、8内含子和6、7、8外显子进行SNPs遗传多态性检测和分析。结果共检测到2个SNPs位点(C1T和C52 T),均为同义突变,利用卡方检验分析,结果表明PEP基因的这2个SNPs位点分别与鳜的食性驯化不具显著相关性(P>0.05)。将2个SNPs位点的不同基因型组合成5种双倍型,卡方检验表明双倍型Dip1与Dip5在两组中存在显著差异(P<0.05)。本研究成功完成鳜PEP基因组多态性分析,因而可以考虑将PEP基因作为影响鳜食性驯化的候选基因。

Sinperca chuatsi refuse to eat dead prey or man-made feed.However,experiments with long-term cul-tivation suggest that S.chuatsi can be domesticated to feed on inert baits.Selective breeding of S.chuatsi using molecular markers and mass cultivation with artificial feed reduces the problems associated with cost,contamina-tion,and disease.Pepsinogen is an acid gaster-digestion hydrolase which digests proteins under acidic conditions.Acidic proleases are sometimes used as additives in animal feed as they promote digestion and absorption of nu-trients in fish.In order to search the distribution of the alleles and genotypes of pepsin gene（PEP） gene between domesticated and undomesticated populations,we identified SNPs in introns 5,6,7,and 8 and exons 6,7,and 8 of the PEP in S.chuatsi using DS,PCR-RFLP,and CRS-PCR.Two SNP sites（T1C,C52T） was identified in exon 7 of the PEP gene,both of which were synonymous mutations.There was not significant difference in the occur-rence of the SNPs between domesticated and undomesticated populations（P0.05）.Five diplotypes were con-structed based on two SNPs in the experimental population.There was a significant association between diplo-type1 and diplotype5 in the two populations（P0.05）.Our results provide a foundation for marker assisted selec-tive breeding.The PEP gene offers considerable potential as a candidate marker for the domesticated feeding phenotype in S.chuatsi.