基于28S rDNA部分序列的石磺科系统发育研究

Phylogenetic Studies of Onchidiidae(Mollusca,Pulmonata)Based on 28S rDNA Partial Sequence

采用PCR技术对采集自中国大陆沿海5地8个群体石磺的28S rDNA部分序列进行扩增。将测序结果与Gen-Bank中的另外3条石磺科贝类的对应序列一起,以小鼠28S rDNA基因序列进行参照,截取D1、D2、D3区域,拼接后进行比对分析。在获得的689bp的序列中,有76个变异位点,28个简约信息位点,A+T平均含量为30.9%,C+G平均含量为69.0%。以分类关系较近的菊花螺科(Siphonaria alternate)为外群,用NJ、MP、ML和贝叶斯法构建分子系统树。4种方法得到的进化树拓扑结构很相似,得到的结果也与沈和定提出的中国大陆沿海石磺科贝类可划分为Peronia、Platevindex、Onchidium、Paraoncidium4个属的观点基本一致。同时,28S rDNA部分序列的系统分析还显示,4个属中Peronia属与Paraoncidium属亲缘关系较近,Platevindex属与Onchidium属关系比较近。

The partial 28S rDNA sequences of 8 populations of Onchidiidae collecting from 5 coastal areas of China were applied using PCR technique.The sequences resulted from sequencing were compared to the other three 28S rDNA sequences of Onchidiidae downloaded from Genbank and the 28S rDNA sequence of mouse.D1,D2,D3 domains of each 28S rDNA sequence were intercepted and then splicing the three domains together for alignment.The length of 28S rDNA sequence of Onchidiidae is 689 bp including 76 variable sites and 28 parsimony informative sites.The average content of A＋T is 30.9%while the G＋C is 69.0%.With Siphonaria alternata as outgroup,phylogenetic trees of NJ,MP,ML and Bayesian were constructed.Cladogram topological structures of the four phylogenetic trees were similar and the result is the same as Shen Heding＇s view point which indicates that the Onchidiidae of Chinese mainland can be divided into 4 genera named Peronia,Platevindex,Onchidium,Paraoncidium.In addition,Peronia was closely related to Paraoncidium and Platevindex was closely related to Onchidium.