基于线粒体DNA D-loop序列的黄斑篮子鱼群体遗传多样性分析

Genetic variations among Siganus oramin populations in coastal waters of southeast China based on mtDNA control region sequences

对中国华南沿海不同地理群体的黄斑篮子鱼(Siganus oramin)进行遗传多样性分析,测定了漳州东山湾(DS)、深圳大亚湾(DY)、深圳大鹏湾(DP)、阳江沙扒湾(SB)4个群体共计100尾黄斑篮子鱼线粒体DNA D-loop序列。结果显示:序列长度约828bp,包含72个变异位点,50个单倍型,A、T、C、G含量平均为31.2%、31.1%、20.8%和16.9%;单倍型多样性指数为0.893±0.053~0.957±0.030,核苷酸多样性指数为0.0105±0.0031~0.0179±0.0031,表现为高单倍型多样性而低核苷酸多样性的特点;群体内的遗传距离0.0107~0.0184,群体间的遗传距离0.0112~0.0172,AMOVA分析显示群体间的分子变异占0.66%,群体内占99.34%;中性检验结果表明Fu’s Fs检验值为显著的负值(-16.7079,p<0.01);核苷酸不配对分布图呈单峰,表明黄斑篮子鱼演化过程中经历过种群扩张事件,推测扩张时间约在1.38~4.60万年前。综上,华南沿海岸4个黄斑篮子鱼群体间不存在显著的遗传分化,可划归一个管理单元,而沙扒湾(SB)群体遗传多样性水平相对较高,应优先加以保护。

In this study,we determined 828 bp mtDNA control region sequences of 100 Siganus oramin individuals collected in Daya Bay,Dapeng Bay,Shaba Bay,and Dongshan Bay where 72 variable sites defined 50 haplotypes.The parameter of haplotype diversity(h)were 0.893±0.053~0.957±0.030,and that of nucleotide diversity(π)was 0.0105±0.0031~0.0179±0.0031,indicating a peculiarity of high haplotype diversity and low nucleotide diversity,The genetic diversity indexes of four geographical groups were,respectively,0.0121(DS),0.0169(DY),0.0107(DP),and 0.0184(SB).A combination of the significant negative neutral test values of Fu’s Fs(-16.7079,p<0.01),the mismatch distribution pattern,and the network analysis revealed that a historical population expansion occurred at about 38300 years ago.The indices of genetic distance among populations(0.0112~0.0172)were at a similar level as the indices of genetic distance within populations(0.0107~0.0184).The overall genetic differentiation index(Fst)was 0.0066(p>0.05),and the analysis of molecular variance showed that most of the genetic variations of the four populations was distributed within populations.With the above findings,it is suggested that S.oramin in the coastal waters of Southeast China is in low level of population genetic diversity and should receive effective protection.