印度-太平洋石鲈亚科鱼类DNA条形码及分子系统进化研究

为探讨DNA条形码基因COⅠ序列在石鲈亚科鱼类物种鉴定的有效性,本研究分析了印度-太平洋区域的石鲈亚科7个属29种鱼类9个个体长度为651 bp的COⅠ基因序列,利用MEGA 5.0计算石鲈亚科种内与种间的遗传距离,并基于最大简约法与最大似然法构建了其分子系统进化关系。结果显示:石鲈亚科鱼类种间遗传距离在0.021—0.240之间,平均遗传距离0.184;种内遗传距离在0.000—0.009之间,平均0.004。其中种间平均遗传距离(0.184)显著大于种内平均遗传距离(0.004),种间遗传距离是种内的46倍。同时,各物种间遗传距离均大于Hebert推荐区分物种的最小种间遗传距离0.02(2%)。基于COⅠ序列构建的系统进化树,同一物种不同个体间均能聚成独立的单系,表明COⅠ基因可作为石鲈亚科物种准确鉴定的有效条形码基因。同时,系统进化树上,石鲈属是非单系类群,主要形成5个分支,而不同分支的种类与其地理分布存在一定的相关性,与近年部分分子系统地理学的研究观点一致。

DNA BARCODING FOR WORLDWIDE HAEMULINAE IN CLASSIFICATION AND PHYLOGENY

To investigate the feasibility of using COI sequences as DNA barcodes in identifying Haemulinae species, the 651 bp COI sequences of 91 Haemulinae individuals from 7 genera 29 species were determined in this study. Genetic distances among and within species were calculated using MEGA 5.0 and the molecular phylogenetic trees were constructed using maximum parsimony and maximum likelihood methods. The result showed that: the genetic distance among inter-species were 0.021-0.240 and the average distance was 0.184, the genetic distance among intra-species were 0.000-0.009 and the average distance was 0.004, the average inter-species value (0.184) was exactly larger than average intra-species value (0.004), and was 46 times larger than the latter. Each interspecies genetic distance value was larger than the minimum species identification value 0.200(2%)suggested by Hebert. In the molecular phylogenetic trees, individuals of the same species each formed an independent monophyletic group, indicating that COI could be used as a potentially effective barcode gene in accurate identification for Haemulinae species. Meanwhile, based on the phylogenetic trees, the Pomadasys fish were found to be non-monophyletic and form 5 independent groups in the trees, however, such phylogenetic relationships were correlated with their geographic distributions, which was consistent with the view of the current molecular phylogeography studies.