Long duplication of 18S ribosomal DNA in Cynoglossus lineolatus(Pleuronectiformes： Cynoglossidae)： novel molecular evidencefor unequal crossing over model

作     者：GONG Li SHI Wei YANG Min SI Lizhen KONG Xiaoyu 

作者机构：Guangxi Key Laboratory of Mangrove Conservation and Utilization Guangxi Mangrove Research Center Guangxi Academy of Sciences Beihai 536000 China Key Laboratory of Tropical Marine Bio-resources and Ecology/Guangdong Provincial Key Laboratory of Applied Marine Biology South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510000 China University of the Chinese Academy of Sciences Beijing 100049 China 

出 版 物：《Acta Oceanologica Sinica》 (海洋学报（英文版）)

年 卷 期：2016年第35卷第12期

页      面：38-50页

核心收录：

学科分类：0710[理学-生物学] 07[理学] 0905[农学-畜牧学] 09[农学] 071007[理学-遗传学] 090501[农学-动物遗传育种与繁殖] 

基　　金：The National Natural Science Foundation of China under contract No.31272273 the Open Research Fund Program of Guangxi Key Laboratory of Mangrove Conservation and Utilization under contract No.GKLMC-201502 

主　　题：nrDNA Cynoglossus lineolatus tandem repeat pseudogene polymorphism non-concerted evolution 

摘      要：Although 18 S r DNA sequence is extremely conservative, the polymorphism still has been found in few *** the present study, three types(Type A, B and C) of 18 S r DNA sequence coexisted in Cynoglossus lineolatus genome, suggesting a non-concerted evolution process, rather than a strictly concerted evolution *** on the differences of sequence variation, GC content, secondary structure and minimum free energy,Types A and B were speculated as the potential pseudogenes. Additionally, a fascinating finding was a 189-bp duplication of 18 S r DNA in Type A sequence. To our knowledge, this is the first report on such a long duplication in teleostean ribosomal DNA. Compared with several theories accounting for the formation of tandem repeats, the unequal crossing over model was thought to be the most likely mechanism to generate the189-bp duplication of 18 S r DNA. These results not only provide a novel molecular evidence for the unequal crossing over model, but also benefit for the further study on 18 S r DNA in fishes.