凡纳滨对虾过氧化氢酶基因单核苷酸多态性及其与耐低溶氧性状的相关性

Single Nucleotide Polymorphisms in Catalase Gene and Their Association with Resistant Hypoxia Traits in Litopenaeus vannamei

采用直接测序法研究凡纳滨对虾（Litopenaeusvannamei)过氧化氢酶（CAT）基因的单核苷酸多态性（SNP），并分析得到的基因型与凡纳滨对虾低溶氧耐受性状的关联性，寻找与凡纳滨对虾耐低溶氧性状相关的SNP标记。结果显示：在CAT基因外显子1第155碱基处发现1个SNP位点，为A→G颠换，表现为同义突变。在凡纳滨对虾群体中该位点等位基因A和G的频率分别为0.146和0.854，多态信息含量PIC值为0.218，属于低度多态性，群体在该基因座上符合哈温（Hardy-Weinberg）平衡(P>0.05)。关联分析表明，CAT基因SNP位点不同基因型与低溶氧耐受性状关联性有统计学意义（χ2=9.277，P=0.002），其中AG型在应激耐受组中占优势地位（52.17%）。CAT基因多态性与凡纳滨对虾低溶氧耐受性相关，可作为影响凡纳滨对虾耐低溶氧性状的候选基因，为凡纳滨对虾选育提供分子遗传标记。

The single nucleotide polymorphisms (SNP) in catalase (CAT) gene was studied betweenhypoxia resistant group and susceptible group of Litopenaeus vannamei by using direct sequencingtechnique, and the association between the polymorphisms and hypoxia tolerance traits was analyzed soas to find the SNP sites and provide the molecular basis for the genetic breeding of L. vannamei. Theresult shows that a SNP site is found in 155 bp of catalase gene, which is A/G transversion andsynonymous with mutation. In this population, allele frequency of A and G is 0.146 and 0.854,respectively. The SNP polymorphic information content (PIC) is 0.218, which in a low degree ofpolymorphism (PIC < 0.25), and the genotypes distribution fitted to the Hardy-Weinberg equilibrium (P> 0.05). The correlation between different genotypes and hypoxia tolerance traits of L. vannamei isanalyzed by chi-square test. The results indicate that the genotypes of intron 1 are significantlyassociated with the hypoxia tolerance traits (χ 2 = 9.277, P < 0.01). Among them, the AG genotype isdominant in the hypoxia tolerance (52.17%). It is suggested that the CAT gene should be one of thecandidates which significantly affect the hypoxia tolerance of L. vannamei, and can be used as the molecular genetic markers applying for L. vannamei breeding.