Biodiv Sci ›› 2009, Vol. 17 ›› Issue (2): 143-150.DOI: 10.3724/SP.J.1003.2009.08286

• Paper • Previous Articles     Next Articles

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

Xuelan Yan, Wenqiao Tang, Jinquan Yang**()   

  1. Laboratory of Fishes, Shanghai Ocean University, Shanghai 201306
  • Received:2008-11-06 Accepted:2009-03-05 Online:2009-03-20 Published:2009-03-20
  • Contact: Jinquan Yang*

Abstract:

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 between CJ and QT were 6%. Phylogenetic trees constructed using maximum likelihood (ML), maximum parsimony (MP) and neighbor-joining (NJ) methods showed similar topology with two well-supported monophyletic 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 million years BP). Climatic oscillations and recurrent marine regression during this period may have influenced the geographical isolation and genetic differentiation of C. mystus.

Key words: Coilia mystus, coastal waters of southeast China, mtDNA control region, genetic diversity, monophyletic group