基于mtDNA COⅠ和Cytb基因序列对南中国海不同海域波纹唇鱼群体遗传多样性的研究

GENETIC DIVERSITY AND DIVERGENCE OF CHEILINUS UNDULATUS OF DIFFERENT GEOGRAPHIC POPULATIONS OF THE SOUTH CHINA SEA REVEALED BY COⅠ AND CYTB GENE ANALYSES

研究以海南陵水、马来西亚、西沙、南沙4个海域共101尾波纹唇鱼作为研究对象,通过线粒体DNA的COⅠ和Cytb基因序列分析方法对波纹唇鱼进行了遗传多样性研究。经PCR扩增、克隆与序列测定,分别获得1560 bp COⅠ基因和1141 bp Cytb基因序列。两者多态性遗传参数统计显示,101尾个体分别存在23(COⅠ)和30(Cytb)个变异位点,分别检测出20(COⅠ)和27(Cytb)个单倍型,总群体单倍型多样性(Hd)分别为0.629(COⅠ)和0.755(Cytb),平均核苷酸差异数(K)分别为1.195(COⅠ)和1.424(Cytb),核苷酸多样性指数(Pi)分别为0.00077(COⅠ)和0.00126(Cytb)。分子方差分析(AMOVA)结果分别为26.26%(COⅠ)和4.22%(Cytb)的变异来自群体间,73.74%(COⅠ)和95.78%(Cytb)的变异来自群体内。同时,两个基因的单倍型网络图呈星状放射结构,不同地理来源的单倍型无明显分支,呈交错分布,没有体现地理差异性。研究初步认为,波纹唇鱼的遗传多样性处于较低水平,遗传分化存在但不显著,该结果可为今后波纹唇鱼的种质资源保护工作提供必要的科学依据。

The genetic diversity of Cheilinus undulatus was studied based on the sequence analysis of mtDNA(COⅠand Cytb) of 101 individuals from four geographical populations including Lingshui(n=31),Malaysia(n=20),Xisha(n=14),and Nansha(n=36).Using PCR amplification and sequencing,1560 bp of COⅠ and 1141 bp of Cytb sequences were obtained.For COⅠ sequences,the number of haplotype is 20,haplotype diversity was 0.629,the nucleotide diversity was 0.00077,the average nucleotide difference was 1.195,and the number of polymorphic site was 23.For Cytb sequences,the number of haplotype was 27,the haplotype diversity was 0.755,the nucleotide diversity was 0.00126,the average nucleotide difference was 1.424,and the number of polymorphic site was 30.AMOVA showed a higher percentage of 73.74% with-population variation than that of 26.26% among-population variation in COⅠ sequences.Similarly,the percentage of 95.78% within-population variations was higher than that of 4.22% the among-population variation in Cytb sequences.The haplotype network of COⅠ and Cytb genes with stellate radiation structure suggested that haplotypes distribution did not have the characteristics of clear geographical differentiation.Genetic diversity was low and the genetic divergence was inconspicuous between populations of C.undulatus.These results may be very useful to protect this species.