基于DNA条形码探讨红树林区背眼虾虎鱼亚科鱼类的分子系统学

Molecular Systematics of Mangrove Oxudercine Gobies(Gobiidae:Oxudercinae) Based on DNA Barcodes

本研究分别基于线粒体的Cox1基因DNA条形码序列和12个蛋白编码基因序列,探讨我国雷州半岛红树林常见9种背眼虾虎鱼的分类与演化历程。采用Kimura双参数法计算遗传距离,基于邻接法(NJ)和最大似然法(ML)构建的系统进化树显示,属于背眼虾虎鱼亚科(Oxudercinae)的弹涂鱼属(Periophthalmus)聚为一枝,呈单系群;大鳍弹涂鱼(P.magnuspinnatus)与弹涂鱼(P.modestus)的平均遗传距离高达12.55%,分属分子系统树的不同分支,从分子水平证实了大鳍弹涂鱼为新纪录种。依化石记录标定的松散分子钟估算物种的分歧时间,推测背眼虾虎鱼亚科与虾虎鱼亚科(Gobiinae)及其它亚科于始新世晚期至渐新世中期(39.48~26.09 Mya)出现了明显的分化,到中新世(27.98~20.03 Mya),背眼虾虎鱼亚科的两栖类型开始出现。本研究表明线粒体Cox1条形码能清楚反映出虾虎鱼类亚科、属及种间分类单元的系统发育关系。

In this study, DNA barcodes sequences of the mitochondrial Cox 1 genes and 12 mitochondrial protein coding genes were used to discuss classification and molecular systematic evolution of 9 common species who were Oxudercine gobies from the mangrove of the Leizhou Peninsula, China. Based on average genetic distances calculated by the Kimura 2-parameter model （K-2P）, phylogenetic trees were recovered using the neighbor joining （N J） and maximum likelihood （ML） methods. Those species of the genus Periophthalmus （Oxudercinae） were cluste- red into the same branch and formed a monophyletic group. The average K-2P distance between P. rnagnuspinnatus and P. modestus was as high as 12.55%. The two species divided into two distant branches, which confirmed that P. mognuspiunatus was a valid species at a molecular level. Relaxed molecular clocks calibrated by fossil records estimated the divergence time, which indicated those subfamilies including Oxudercinae, Gobiinae and others, had a significant differentiation in the late Eocene to medium-term Oligocene （39.48-26.09 Mya）, and amphibian type of Oxudercinae occurred in early Miocene （27.98-20.03 Mya）. The study indicated that mitochon- drial Coxl barcodes could be useful for the phylogenetic relationships on different taxonomic levels of subfamily, genera and species.