7种金鱼线粒体基因组比较

Comparison of Mitochondrial Genomes of Seven Kinds of Carassius auratus auratus

为比较不同金鱼品种线粒体基因组的差异,通过PCR对虎头、红头白蛋、红白文、高头红文、墨龙睛、黑水泡眼和红朝天龙共7种金鱼线粒体基因组进行扩增,利用Clustal Omega和Contig Express等软件进行序列的比对和拼接,并利用MEGA 7.0和DNA SP 5.0等软件分析不同品种金鱼的线粒体基因组的基本特征、基因排列以及基因组序列的差异情况。结果表明:7种金鱼线粒体基因组全序列长度均为16580bp,基因排列顺序完全相同,排列紧凑,均含13个蛋白质编码基因、22个tRNA、2个rRNA、1个非编码控制区(D-loop区)和1个轻链复制起始区(OL区);ND6和8个tRNA基因在L链上编码,其他基因均在H链上编码。金鱼线粒体基因组和13个编码蛋白的基因的碱基组成具有AT偏好性,A+T含量分为57.7%和58.1%;预测了金鱼22个tRNA的二级结构,大部分tRNA基因都形成典型的三叶草结构,仅tRNA^(Ser)(AGN)缺少DHU臂。在D-loop区中的识别出1个终止序列区(TAS)、3个中央保守区(CSB-F、CSB-E和CSB-D)和3个保守序列区(CSB-1、CSB-2和CSB-3)。对线粒体基因组的全序列比对结果显示,仅存在4个变异位点,且均为非简约信息位点,其中D-loop区变异位点1个,ND2基因2个,ND5基因1个。7种金鱼的线粒体基因组缺乏简约性信息位点,因此线粒体基因组或基因在金鱼系统发育提供的遗传信息将十分有限。

In order to compare the differences in the mitochondrial genome from seven kinds of goldfish, Carassius auratus auratus, the mitochondrial genome sequences of seven kinds of goldfish, including Tigerhead oval, White oval with Red head,Red and white fantail, Red lionhead fantail, Black dragon-eye, Black bubble eye and Red Celestial dragon-eye, were determined by using conventional PCR. The complete mitochondrial genome sequences were matching and splicing by software Clustal Omega and Contig Express etc., and the basic characteristics and gene arrangement of C. auratus auratus mitochondrial genome were analyzed by software MEGA 7.0 and DNA SP 5.0 etc. Moreover, the diversity of the seven kinds of C. auratus auratus mitochondrial genome was analyzed. The results showed that the entire mitochondrial genome of the seven kinds of C. auratus auratus were all 16580 bp in length, consisting of 13 protein-coding genes, 22 tRNA genes and two r RNA genes and, a non-coding control region（D-loop） and a replication origin region of the light chain（OL）, with identical arrangement and tightly packed. ND6 and eight tRNAs genes were encoded on the light strand（L strand）, and the remainders encoded on the heavy strand（H strand）. The composition of C. auratus auratus mitochondrial DNA base and all 13 protein-coding genes have AT preference, with 57.7% and 58.1% A ＋T content respectively. The secondary structure of tRNA of C. auratus auratus was predicted. The secondary structures of 22 tRNA have the typical clover exception of tRNASer（AGN） owing to the lack of ＂DHU＂arm. A termination sequence（TAS）, three central conservative（CSB-F, CSB-E and CSB-D） and three conservative sequence areas（CSB-1, CSB-2 and CSB-3） were identified in the control region. The comparison of the complete mitochondrial genome sequences showed that there were four variable sites,which were all singleton variable sites. One variable site was found in control region, and two in the ND2 gene, as well as one in the ND5 gene. The lack of the parsimony informative site of the whole mitochondrial genome indicated that the information provided by the mitochondrial genome or gene in the study of phylogenetic and population genetics of C. auratus auratus could be restricted.