线纹舌鳎(Cynoglossus lineolatus)18S rRNA基因长片段复制:不等交换模型(unequal crossing over model)罕见的分子证据
doi: 10.1007/s13131-016-0957-z
Long duplication of 18S ribosomal DNA in Cynoglossus lineolatus (Pleuronectiformes: Cynoglossidae): novel molecular evidence for unequal crossing over model
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摘要: 尽管18S rRNA基因序列极其保守,但是在一些种类中仍然发现其存在序列多态性。本研究在线纹舌鳎18S rRNA基因中发现了3种差异显著的序列类型(Type A,B和C),说明其为非协同进化,而不是严格遵循协同进化方式。基于以上三种类型序列GC含量、二级结构、最小自由能等差异,我们推测Type A和B可能是假基因类型。此外,在Type A类型中还发现了一段长达189 bp的重复序列。据我们所知,如此长的重复序列,这在硬骨鱼类核糖体基因中还是首次报道。通过比较分析产生重复序列常见的模型,我们认为不等交换模型最有可能解释该重复序列的形成。本研究结果不仅为不等交换模型提供了罕见的分子证据,而且为鱼类18S rRNA基因研究奠定了很好的基础。Abstract: Although 18S rDNA sequence is extremely conservative, the polymorphism still has been found in few species. In the present study, three types (Type A, B and C) of 18S rDNA sequence coexisted in Cynoglossus lineolatus genome, suggesting a non-concerted evolution process, rather than a strictly concerted evolution fashion. Based 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 18S rDNA 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 the 189-bp duplication of 18S rDNA. These results not only provide a novel molecular evidence for the unequal crossing over model, but also benefit for the further study on 18S rDNA in fishes.
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Key words:
- nrDNA /
- Cynoglossus lineolatus /
- tandem repeat /
- pseudogene /
- polymorphism /
- non-concerted evolution
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Alverson A J, Kolnick L. 2005. Intragenomic nucleotide polymorph-ism among small subunit (18S) rDNA paralogs in the diatom genus Skeletonema (Bacillariophyta). J Phycol, 41(6):1248-1257 Bailey C D, Carr T G, Harris S A, et al. 2003. Characterization of angio-sperm nrDNA polymorphism, paralogy, and pseudogenes. Mol Phylogenet Evol, 29(3):435-455 Benevolenskaya E V, Kogan G L, Tulin A V, et al. 1997. Segmented gene conversion as a mechanism of correction of 18S rRNA pseudogene located outside of rDNA cluster in D. melano-gaster. J Mol Evol, 44(6):646-651 Benson G. 1999. Tandem repeats finder:a program to analyze DNA sequences. Nucleic Acids Res, 27(2):573-580 Broughton R E, Dowling T E. 1994. Length variation in mitochondrial DNA of the minnow Cyprinella spiloptera. Genetics, 138(1):179-190 Buroker N E, Brown J R, Gilbert T A, et al. 1990. Length heteroplasmy of sturgeon mitochondrial DNA:an illegitimate elongation model. Genetics, 124(1):157-163 Carranza S, Giribet G, Ribera C, et al. 1996. Evidence that two types of 18S rDNA coexist in the genome of Dugesia (Schmidtea) medi-terranea (Platyhelminthes, Turbellaria, Tricladida). Mol Biol Evol, 13(6):824-832 Chen Shanmin, Ma Kayan, Zeng Jin. 2011. Pseudogene:lessons from PCR bias, identification and resurrection. Mol Biol Rep, 38(6):3709-3715 Chen Ziyi, Xiong Zhujun, Pan Xiaoyun, et al. 2015. Variation of gen-ome size and the ribosomal DNA ITS region of Alternanthera philoxeroides (Amaranthaceae) in Argentina, the USA, and China. J Syst Evol, 53(1):82-87 Edwards Y J K, Elgar G, Clark M S, et al. 1998. The identification and characterization of microsatellites in the compact genome of the Japanese pufferfish, Fugu rubripes:perspectives in func-tional and comparative genomic analyses. J Mol Biol, 278(4):843-854 Ellegren H. 2000. Microsatellite mutations in the germline:implica-tions for evolutionary inference. Trends Genet, 16(12):551-558 Harpke D, Peterson A. 2007. Quantitative PCR revealed a minority of ITS copies to be functional in Mammillaria (Cactaceae). Int J Plant Sci, 168(8):1157-1160 Harris D J, Crandall K A. 2000. Intragenomic variation within ITS1 and ITS2 of freshwater crayfishes (Decapoda:Cambaridae):im-plications for phylogenetic and microsatellite studies. Mol Biol Evol, 17(2):284-291 Keller I, Chintauan-Marquier I C, Veltsos P, et al. 2006. Ribosomal DNA in the grasshopper Podisma pedestris:escape from con-certed evolution. Genetics, 174(2):863-874 Krieger J, Hett A K, Fuerst P A, et al. 2006. Unusual intraindividual variation of the nuclear 18S rRNA gene is widespread within the Acipenseridae. J Hered, 97(3):218-225 Kumar R, Singh M, Kushwaha B, et al. 2013. Molecular characteriza-tion of major and minor rDNA repeats and genetic variability assessment in different species of mahseer found in North In-dia. Gene, 527(1):248-258 Larkin M A, Blackshields G, Brown N P, et al. 2007. Clustal W and Clustal X version 2.0. Bioinformatics, 23(21):2947-2948 Levinson G, Gutman G A. 1987. Slipped-strand mispairing:a major mechanism for DNA sequence evolution. Mol Biol Evol, 4(3):203-221 Li Yi, Jiao Lei, Yao Yijian. 2013. Non-concerted ITS evolution in fungi, as revealed from the important medicinal fungus Ophiocordy-ceps sinensis. Mol Phylogenet Evol, 68(2):373-379 Long E O, Dawid I B. 1980. Repeated genes in eukaryotes. Annu Rev Biochem, 49(1):727-764 Melters D P, Bradnam K R, Young H A, et al. 2013. Comparative ana-lysis of tandem repeats from hundreds of species reveals unique insights into centromere evolution. Genome Biol, 14(1):R10 Merlo M A, Cross I, Chairi H, et al. 2010. Analysis of three multigene families as useful tools in species characterization of two closely-related species, Dicentrarchus labrax, Dicentrarchus punctatus and their hybrids. Genes Genet Syst, 85(5):341-349 Nyaku S T, Sripathi V R, Kantety R V, et al. 2013. Characterization of the two intra-individual sequence variants in the 18S rRNA gene in the plant parasitic Nematode, Rotylenchulus reniformis. PLoS One, 8(4):e60891 Okada K, Yamazaki Y, Yokobori S, et al. 2010. Repetitive sequences in the lamprey mitochondrial DNA control region and speciation of Lethenteron. Gene, 465(1-2):45-52 Platas G, Polishook J D, Peláez F. 2002. VNTR polymorphism in the ITS1 region (rDNA) in isolates of a Nodulisporium species. Mycol Res, 106(11):1293-1298 Rouchka E C. 2010. Database of exact tandem repeats in the Zebrafish genome. BMC Genom, 11:347 Santos S R, Kinzie Ⅲ R A, Sakai K, et al. 2003. Molecular characteriza-tion of nuclear small subunit (ISS)-rDNA pseudogenes in a symbiotic dinoflagellate (Symbiodinium, Dinophyta). J Euka-ryot Microbiol, 50(6):417-421 Shi Wei, Kong Xiaoyu, Wang Zhongming, et al. 2013. Pause-melting misalignment:a novel model for the birth and motif indel of tandem repeats in the mitochondrial genome. BMC Genom, 14(1):103 Smith G P. 1974. Unequal crossover and the evolution of multigene families. Cold Spring Harb Symp Quant Biol, 38:507-513 Suzuki M T, Giovannoni S J. 1996. Bias caused by template annealing in the amplification of mixtures of 16S rRNA genes by PCR. Ap-pl Environ Microbol, 62(2):625-630 Szostak J W, Wu R. 1980. Unequal crossing over in the ribosomal DNA of Saccharomyces cerevisiae. Nature, 284(5755):426-430 Varadaraj K, Skinner D M. 1994. Denaturants or cosolvents improve the specificity of PCR amplification of a G + C-rich DNA using genetically engineered DNA polymerases. Gene, 140(1):1-5 Waye J S, Willard H F. 1986. Molecular analysis of a deletion poly-morphism in alpha satellite of human chromosome 17:evid-ence for homologous unequal crossing-over and subsequent fixation. Nucleic Acids Res, 14(17):6915-6927 Won H, Renner S S. 2005. The internal transcribed spacer of nuclear ribosomal DNA in the gymnosperm Gnetum. Mol Phylogenet Evol, 36(3):581-597 Xu Jianpeng, Zhang Quanqi, Xu Xiaofei, et al. 2009. Intragenomic variability and pseudogenes of ribosomal DNA in Stone flounder Kareius bicoloratus. Mol Phylogenet Evol, 52(1):157-166 Zhao Ying, Strope P K, Kozmin S G, et al. 2014. Structures of naturally evolved CUP1 tandem arrays in yeast indicate that these arrays are generated by unequal nonhomologous recombination. G3-Genes Genom Genet, 4(11):2259-2269 Zuker M. 2003. Mfold web server for nucleic acid folding and hybrid-ization prediction. Nucleic Acids Res, 31(13):3406-3415
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