西藏拟溞Daphniopsis tibetana核糖体18S和ITS2序列克隆及进化分析  

Cloning and phylogenetic analysis ribosomal 18S and ITS2 sequences in Daphniopsis tibetana Sars

作　　者：史楠冰 赵文 刘卫东[2] 魏杰 安浩 季世琛 SHI Nan-bing;ZHAO Wen;LIU Wei-dong;WEI Jie;AN Hao;JI Shi-chen(College of Fisheries and Life Science,Dalian 116023,China;Dalian Ocean University,Liaoning Ocean and Fisheries Science Research Institute,Dalian 116023,China)

机构地区：[1]大连海洋大学水产与生命学院,大连116023 [2]辽宁省海洋水产科学研究院,大连116023

出　　处：《生物学杂志》2018年第6期37-41,共5页Journal of Biology

基　　金：国家科技基础性工作专项(2014FY210700)

摘　　要：利用PCR反应扩增出西藏拟溞Daphniopsis tibetana核糖体18S和转录间隔区II (ITS2)片段,经克隆测序后获得其序列,在此基础上研究西藏拟溞分类进化地位。西藏拟溞18S rDNA序列长2296 bp,A、T(U)、G、C含量分别为21.2%、24.4%、29.8%和24.6%; ITS2序列长度平均为1229 bp,A、T(U)、G、C含量平均为28.3%、23.5%、25.5%及22.7%。采用最大似然法(ML)构建的18S rDNA系统进化树显示,西藏拟溞D.tibetana和方角拟溞D.quadrangula亲缘关系最近,在进化树上聚集在同一分支;和溞属的大型溞Daphnia magna在不同分支上,该结果再次证明了西藏拟溞在分类上应归属于拟溞属。与18S rDNA相比,西藏拟溞ITS2序列存在个体间碱基及长度差异,与同科异属物种之间差异更大。获得的西藏拟溞18S rDNA、ITS2序列,为该种进一步的分子水平研究提供了基础数据。In this article,the ribosomal 18S and the second internal transcribed spacer(ITS2)sequences of the Daphniopsis tibetana Sars were amplified and the evolutionary status were investigated.The results showed that the length of 18S rDNA sequence was 2296 bp,the contents of A,T(U),G and C were 21.2%,24.4%,29.8%and 24.6%,respectively,the average length of ITS2 sequence was 1229 bp,while the contents of A,T(U),G and C were 28.3%,23.5%,25.5%,22.7%,respectively.The phylogenetic tree was constructed with the maximum likelihood method(ML)by MEGA5.0 software.It is showed that the genetic relationship between D.tibetana and D.quadrangula was so closest to clustere in the same branch.However,D.tibetana and Daphnia magna were clustered on different branches.It is confirmed that D.tibetana should be classified in the Daphniopsis genus,which is consistent with the previous studies.Compared with 18S rDNA,there were differences in base and length among the ITS2 sequences in D.tibetana.The divergence were obvious among the same family but different genera.The 18S rDNA and ITS2 sequences obtained from this study provide the basic data for the further molecular studies of D.tibetana.

关 键 词：西藏拟溞 18SrDNA ITS2 遗传距离 进化分析 

分 类 号：Q78[生物学—分子生物学]