生物多样性 ›› 2009, Vol. 17 ›› Issue (2): 143-150.doi: 10.3724/SP.J.1003.2009.08286

• 论文 • 上一篇    下一篇

基于线粒体控制区的序列变异分析中国东南部 沿海凤鲚种群遗传结构

阎雪岚, 唐文乔, 杨金权*   

  1. 上海海洋大学鱼类研究室, 上海 201306
  • 出版日期:2009-03-20
  • 通讯作者: 杨金权

Population genetic structure of tapertail anchovy (Coilia mystus) in coastal waters of southeast China based on mtDNA control region se-quences

Xuelan Yan, Wenqiao Tang, Jinquan Yang*   

  1. Laboratory of Fishes, Shanghai Ocean University, Shanghai 201306
  • Online:2009-03-20
  • Contact: Jinquan Yang

为了解中国东南部沿海凤鲚(Coilia mystus)的种群遗传多样性和遗传结构, 本文分析了长江口(CJ)、钱塘江口(QT)、闽江口(MJ)和九龙江口(JL)4个凤鲚地理群体的mtDNA控制区561 bp片段的序列变异。65尾样本共检测到28个单元型。4个群体总的单元型多样性和核苷酸多样性均较高(h = 0.9433 ± 0.0168, π = 0.0317 ± 0.0158), 但单个群体的核苷酸多样性水平却很低, 其中以CJ最高(π = 0.0080 ± 0.0046), MJ最低(π = 0.0015 ± 0.0013)。MJ与JL群体之间以及CJ与QT群体之间的平均K2P遗传距离很小, 分别为0.3%和0.8%; 而CJ、QT分别与MJ、JL群体之间的遗传距离均较大, 达到了6%。采用最大似然法(ML)、最大简约法(MP)和邻接法(NJ)分别构建的单元型间的系统发育树揭示, 4个凤鲚群体构成CJ-QT 和MJ-JL 2个支系, 且具有极高的支持率。单元型的网络分析也显示这两个支系间有高达28步的突变次数。AMOVA分析显示大部分的遗传变异来自这两支系群体间(90.77%), 表明凤鲚群体间存在着显著的地理分化。种群分化指数和基因流分析也表明, 支系间群体有着明显的遗传分化(FST > 0.9, Nm < 0.03)。所有分析结果支持所研究的凤鲚标本属于两个不同的地理种群, 且种群的分化至少已达到亚种水平。采用BEAST和TRACER软件得到凤鲚两个亚种的最近共同祖先约在0.34–0.46百万年前, 处于更新世晚期, 推测可能是第四纪晚期的气候旋回和海平面的升降导致了凤鲚的种群分化。

To analyze the genetic diversity and genetic structure of Coilia mystus, 65 individuals were sampled from four localities, including the Minjiang (MJ), Jiulongjiang (JL), Yangtze (CJ) and Qiantang rivers (QT). Mitochondrial DNA variation was analyzed using 561 bp segments of control region, among which 28 haplotypes were detected. The CJ population had the highest nucleotide diversity (0.0080 ± 0.0046) while the MJ population had the lowest (0.0015 ± 0.0013). Overall haplotype and nucleotide diversity were 0.9433 ± 0.0168 and 0.0317 ± 0.0158, respectively. Average pairwise Kimura 2-parameter distances between MJ and JL and between CJ and QT were 0.3% and 0.8%, respectively, while those between MJ and JL as well be-tween CJ and QT were 6%. Phylogenetic trees constructed using maximum likelihood (ML), maximum par-simony (MP) and neighbor-joining (NJ) methods showed similar topology with two well-supported mono-phyletic groups. The haplotypes from MJ and JL formed a monophyletic group sister to that comprising the haplotypes of CJ and QT. This interrelationship was supported by network analysis with 28 mutation steps between the two monophyletic clades. Analysis of molecular variance (AMOVA) revealed that the variation between the MJ-JL and CJ-QT clades accounted for 90.77% of total variation, suggesting that significant geographical division was present. The low level of gene flow (Nm < 0.03) and high population differentiation values (FST > 0.9) of the two clades also showed considerable genetic isolation. Our results suggest that these four C. mystus populations are divided into two geographical units, and that these units might be considered at the subspecies level in terms of genetic data. The molecular clock estimated using BEAST and TRACER softwares indicated that the subdivision of C. mystus occurred in the late Pleistocene (about 0.34–0.46 mil-lion years BP). Climatic oscillations and recurrent marine regression during this period may have influenced the geographical isolation and genetic differentiation of C. mystus.

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