基于16s rRNA基因片段的长臂虾科系统发育初步研究

长臂虾科(Caridea:Palaemonidae)是真虾类中最大的科级单元之一,为了探索长臂虾科内部的系统演化关系,作者采用从Genbank中下载的长臂虾科两亚科(Palaemoninae,Pontoniinae)14属30种长臂虾的线粒体16s rRNA基因序列片段,以鼓虾科(Alpheidae)细足鼓虾(Alpheus gracilipes)为外群分析长臂虾亚科和隐虾亚科之间的系统发育关系。在获得的466个序列位点中,变异位点263个,简约信息位点213个。DNA序列分析显示,隐虾亚科的德曼隐虾属(Manipontonia)与长臂虾亚科的遗传距离(0.211)要小于其与所在亚科的遗传距离(0.245);此属在基于贝叶斯法(BI)和邻接法(NJ)构建的系统发育树中也与长臂虾亚科的种属聚合为一支,然后与隐虾亚科种属聚合的一支成为姊妹群。结合此属与长臂虾亚科尾瘦虾属(Urocaridella)形态相似的特征,建议对德曼隐虾属在长臂虾科中的分类地位进行重新评估。除隐虾亚科德曼隐虾属聚合到长臂虾亚科聚类簇外,两亚科所属的其他种属各自聚合为一支,在系统树中互为姊妹群,支持将长臂虾分为两亚科的分类系统。

A preliminary phylogenetic analysis of the family Palaemonidae (Caridea: Palaemonoidea) based on mitochondrial 16s rRNA gene

The molecular phylogenetic relationship between the two subfamilies of Palaemonidae Rafinesque (Palaemoninae Rafinesqueand Pontoniinae Kingsley) were reconstructed based on partial sequences of the mitochondrial 16s rRNA gene retrieved from GenBank. The aligned sequences dataset contained 14 genera, 30 sequences of the mitochondrial 16s rRNA gene of palaemonid shrimps, and one species from Alpheidae Rafinesque, 9(Alpheus gracilipes Stimpson), as negative control. Sequence analysis showed that there were 263 variable sites and 213 parsimony informative sites among the total 466 base sites in the aligned dataset. The average content of A+T was 66.3%, significantly higher than G+C, indicating that the base compositions were biased in favor of A+T. The DNA genetic distance analysis showed that the genus Manipontonia Bruce had a smaller genetic distance to the subfamily Palaemoninae (0.211) than to its coordinal genera in subfamily Pontoniinae (0.245). It was consistent with the molecular phylogenetic tree constructed by Bayesian inference and Neighbor-joining methods. In the phylogenetic tree, the genus Manipontonia clustered in the assemblage of Palaemoninae rather than in the cluster of Pontoniinae. Furthermore, this genus is more similar to the Palaemoninae genus Urocaridella Borradailein morphology. The morphology and molecular evidences suggested the systematic status of the genus Manipontonia needs to be re-evaluated. Genus Manipontonia andthe two clustered subfamilies are sister groups, supporting the two subfamilies scheme of Palaemonidae.