摘要
为阐述过度捕捞后中国现存鳓(Ilisha elongata)资源的种质状况,采用16SrRNA基因测序技术对青岛、舟山、厦门和广州4个鳓地理群体的种群结构及遗传变异进行研究。通过对4个鳓群体共45个个体的线粒体16SrRNA基因进行测序,获得1个长度为657bp的同源序列。45个个体中共检测到32个多态位点,多态位点比例达4.88%,其中插入或缺失位点10个;45个个体中检测出20个单倍型,单倍型多样性指数(H)达0.812,核苷酸多样性指数(Pi)达0.0031,平均核苷酸差异数(K)达2.016。结果表明,中国现存鳓种群仍具较高的遗传多样性水平。对4个群体的遗传结构进行检测表明,青岛群体与其他3个群体间存在显著的遗传分化,两个类群间存在1个固定位点的核苷酸差异,分化系数(Fst)达0.3852(P<0.01),基因流(Nm)为0.7980;而舟山、厦门和广州这3群体内部则无显著遗传分化(P>0.01);AMOVA检测显示,69.48%的遗传差异存在于群体内部,而30.52%的遗传差异存在于群体间;聚类分析结果和单倍型网络关系图也证实上述鳓群体的地理分化。推测青岛群体的分化可能与晚更新世以来频繁的海平面变化有关。
To know the resource status of Ilisha elongata after long-term of overfishing,mitochondrial DNA（mtDNA） sequence of 16S rRNA was used to investigate the genetic structure and genetic variatiaon of four populations of Ilisha elongata in coastal waters of China.Partial sequence of 657 bp was obtained through sequencing the 16S rRNA gene of 45 individuals from four I.elongata populations.Thirty-two polymorphic sites were detected in the 657 bp nucleotide,accounting for 4.88%of total sites of 16S rRNA gene sequence.Ten insertion/deletion sites were also observed.Twenty hapotypes were detected out of 45 individuals from four populations.The hapotype diversity index（H）,mean nucleotide diversity index（P i ）and average number of nucleotide differences（K）reached 0.812, 0.003 1 and 2.016,respectively.Results above showed that despite long time of overfishing,Ilisha elongata still keeps plentiful genetic variation in its natural populations.Molecular variance analysis revealed significant genetic divergence between Qingdao population and other three populations.A fixed nucleotide substitute was detected in 16S rRNA gene region between samples from Qingdao population and those from other three populations of Guangzhou,Xiamen and Zhoushan.Genetic divergence Fst and gene flow N m between the two lineages reached 0.385 2 （P0.01）and 0.798 0,while no significant divergence was detected between Guangzhou,Xiamen and Zhoushan populations（P0.05）.AMOVA test showed that 69.48%genetic variation lies in intra-populations and 30.52%lies in intra-populations.UPGMA tree and reduced median network of haplotypes also proved the gentic differentiation between Qingdao population and other three populations.It was postulated that the frequent osilation of sea level during the late Pleistocene might be the cause of differetiation between the two lineages.These findings will act as a stepstone for better protection and development of I.elongata resources in China in the near future.
出处
《中国水产科学》
CAS
CSCD
北大核心
2010年第3期463-470,共8页
Journal of Fishery Sciences of China
基金
国家科技支撑计划项目(2007BAD43B00)
浙江省重大科技攻关国际合作项目(2006C14017)
