摘要
小黄鱼（Pseudosciaena polyactis）为我国重要海产经济鱼类之一, 过度捕捞和环境污染等因素造成其资源日益衰退。研究小黄鱼种群遗传结构对其资源的保护及其可持续利用有十分重要的意义。该研究采用聚合酶链式反应（PCR）技术对浙江舟山附近海域小黄鱼种群53个个体的mtDNA D-loop区全序列进行扩增, 序列长度在795-801bp 之间, 长度差异不大。采用Clustal X1.83、MEGA3.1、DnaSP4.0等生物信息学软件进行遗传多样性分析, 结果显示：53条小黄鱼线粒体DNA D-loop 区的T、C、A 和G 碱基平均含量分别为30.3%、23.1%、32.3%和14.3%, 排除13 处核苷酸的插入或缺失后, 共检测到93处转换和颠换位点, 约占分析序列总长度的11.6%, 其中包括53 个单一多态位点和40 个简约信息位点, 共确定了52 种单倍型, 单倍型多样性（hd）为0.9993, 单倍型间的平均遗传距离为0.012, 转换/颠换平均值为4.305, 平均核苷酸差异数（k）为9.73875, 核苷酸多样性（π）为0.01233,表明舟山小黄鱼遗传多样性处于中等水平。
Pseudosciaena polyactis is an economically important species of marine fish in China that is currently declining due to overexploitation, environmental pollution and related factors. Research in to the genetic structure of Pseudosciaena polyactis populations plays a key role in protecting and promoting sustainable utilization. We collected 53 individuals of Pseudosciaena polyactis from Zhoushan, Zhejiang and sequenced and amplified the mitochondrial DNA （mtDNA） D-loop region using Polymerase Chain Reactions （PCR）. The sequence length of the 53 individuals ranged from 795 to 801 bp. The sequences were analyzed by Clustal X1.83, MEGA3.1 and DnaSP4.0. The results showed that the average base content of T, C, A, G was 30.3%, 23.1%, 32.3% and 14.3%, respectively and there were 93 transition or transversion sites, including 53 single nucleotide mutation sites and 40 parsimony informative sites, which accounted for 11.6% of the length of the analyzed sequences. In total, we identified 52 haplotypes and found haplotype diversity （hd） of 0.9993, average number of nucleotide differences were 9.73875 （k）, and nucleotide diversity （π） of 0.01233. The average genetic distance of haplotypes was 0.012, and the average transition/transversion was 4.305. Based on mitochondrial DNA D-loop region sequences, these results indicate that the genetic diversity of the Pseudosciaena polyactis population in Zhoushan is currently at a medium level.
