褶纹冠蚌线粒体基因组全序列分析

采用LA-PCR(Long amplification polymerase chain reaction)扩增方法首次获得褶纹冠蚌(Cristariaplicata)线粒体基因组全序列。分析表明:序列全长15712bp,包括13个蛋白质基因、22个tRNA基因、2个rRNA基因和26个长度为2～328bp的非编码区。A、T、C、G碱基组成分别为36.54%、27.22%、23.22%、13.02%。大部分基因在L链编码,其中ND3～ND5、ND4L、COI～COIII、ATP6、ATP8、tRNAAsp和tRNAHis在H链编码。基因排列与同科的射线佩饰真珠蚌(Lampsilis ornata)一致,与三角帆蚌(Hyriopsis cumingii)在COII和12SrRNA之间存在差异。13个蛋白质基因具有I(AUU、AUC)、V(GUG)、M(AUA、AUG)3种起始密码子,除ND2终止密码子为不完整的T,其余基因均为典型的UAA或UAG。22个tRNA中,除tRNAThr、tRNALys、tRNASer(UCN)、tRNAAsp、tRNAArg、tRNATyr和tRNAMet之外,其他15个tRNA都具有典型三叶草结构。与其他淡水双壳贝类一样,褶纹冠蚌具有ATP8基因,该基因可能与细胞质的渗透压平衡有关。

Analysis of complete mitochondrial genome of Cristaria plicata

The complete mitochondrial genome of Cristaria plicata was obtained using long amplification polymerase chain reaction (LA-PCR). Analysis showed that the total length of sequence was 15 712 bp, including 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and 26 non-coding regions ranged from 2 bp to 328 bp in size. The nucleotide composition of A, T, C, G were 36.54% 27.22% 23.22% and 13.02%, respectively. Most genes were encoded on the L strand, While ND3-ND5, ND4L, COI-COIII, ATP6, ATP8, tRNA^Asp, and tRNA^His were encoded on the H strand. The arrangement of genes in C. plicata was identical to that of Lampsilis ornata, but was different from that of Hyriopsis cumingii between COII and 12S rRNA in the same family. Thirteen protein genes contained 3 initiation codons, i.e., I (AUU, AUC), V (GUG), and M (AUA, AUG), all of which had complete stop codons (UAA or UAG), except for the stop codon in ND2 that had an incomplete T. Fifteen tRNAs had typical cloverleaf structure, except for tRNAThr, tRNALys, tRNA^Ser(UCN), tRNA^Asp, tRNA^Arg, tRNA^Tyr, and tRNA^Met. Like other freshwater bivalvia, C. plicata contained ATP8 gene, which might be related to the balance of osmotic pressure in the cytoplasm.