Huang Y N, Li J, Jiang Q Y, Shen X S, Yan X Y, Tang Y B, Huang J, Guo Y F, Lan G Q, Jiang H S
College of Animal Science and Technology, Guangxi University, Nanning, China.
College of Animal Science and Technology, Guangxi University, Nanning, China
Genet Mol Res. 2015 Apr 13;14(2):3234-43. doi: 10.4238/2015.April.13.2.
In the present study, the complete mitochondrial (mt) genome of Cyclemys dentata was determined using PCR reactions. The structural organization and gene order of C. dentata were equivalent to those of most other vertebrates. The mt genome was 16,489 bp in length, has rich A+T content, consisting of 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and a control region (D-loop). All protein-coding genes started with ATG, many genes have complete stop codons, except ND2, COX3, ND3, and cyt-b genes had incomplete stop codons of T. The light-strand replication origin (OL) of C. dentata might fold into a stable stem-loop secondary structure, and its loop had 2 nt less than that of the Cyclemys atripons OL sequence. The D-Loop of C. dentata contained a central domain (CD), 2 extended termination associated sequences (ETAS1, ETAS2) and 3 conserved sequence blocks (CSB1, CSB2, CSB3). The average length of 20 turtles' mt genomes was 16,692.5 bp, including 34.1% A, 27.0% T, 26.0% C and 12.9% G. The C. dentata mitochondrial genome could provide useful data for further studies on phylogenetics and conservation genetics of this species. The phylogenetic relationships of the family Geoemydidae were analyzed by maximum-likelihood (ML) and neighbor-joining (NJ) based on concatenated sequences of 13 protein-coding genes from 20 turtle species. The ML and NJ trees had homologous topologies. The results support the existing classification of the genera of Geoemydidae, that C. dentata was a sister species of C. atripons, Pyxidea nested in Cuora, and Chinemys was synonymous with Mauremys.
在本研究中，利用聚合酶链式反应（PCR）确定了齿缘摄龟（Cyclemys dentata）的完整线粒体（mt）基因组。齿缘摄龟的结构组织和基因顺序与大多数其他脊椎动物的相同。该线粒体基因组长度为16,489碱基对，富含A+T含量，由13个蛋白质编码基因、2个核糖体RNA基因、22个转运RNA基因和一个控制区（D环）组成。所有蛋白质编码基因均以ATG起始，许多基因具有完整的终止密码子，除了ND2、COX3、ND3和细胞色素b（cyt-b）基因具有不完全的T终止密码子。齿缘摄龟的轻链复制起点（OL）可能折叠成稳定的茎环二级结构，其环比锯缘摄龟（Cyclemys atripons）OL序列少2个核苷酸。齿缘摄龟的D环包含一个中央结构域（CD）、2个延伸终止相关序列（ETAS1、ETAS2）和3个保守序列块（CSB1、CSB2、CSB3）。20种龟线粒体基因组的平均长度为16,692.5碱基对，包括34.1%A、27.0%T、26.0%C和12.9%G。齿缘摄龟线粒体基因组可为该物种的系统发育和保护遗传学的进一步研究提供有用数据。基于20种龟类13个蛋白质编码基因的串联序列，通过最大似然法（ML）和邻接法（NJ）分析了地龟科的系统发育关系。ML树和NJ树具有同源拓扑结构。结果支持地龟科现有属的分类，即齿缘摄龟是锯缘摄龟的姐妹种，木纹龟属（Pyxidea）嵌套在闭壳龟属（Cuora）中，中华草龟（Chinemys）与黄喉拟水龟（Mauremys）同义。
