Abstract
The complete mitochondrial genome of Elaphe carinata was sequenced and analysed using muscle tissue for the first time. The genome is 17 154 bp in length. The complete mitochondrial genome contains 22 tRNA genes, 13 protein-coding genes (PCGs), two rRNA genes, two control regions (CRI and CRII) and one putative origin of L-strand replication. The gene order and nucleotide composition of E. carinata are very similar with E. davidi, E. schrenckii, E. anomala and E. bimaculata. A phylogenetic tree of mitochondrial genomes analyses of 16 species snakes of Colubridae was made based on the Neighbour-Joining (NJ) method, E. carinata has the most closely relationship with E. davidi, while E. poryphyracea and Euprepiophis perlacea are special species.
Elaphe carinata belonging to genus Elaphe of family Colubridae, is a large, ferocious and non-toxic snake, in China is mainly distributed in the south. It can be used for the treatment of epilepsy, pharyngitis, scrofula, scabies and other symptoms. In this study, complete mitochondrial genome of the E. carinata was sequenced and analysed for the first time using muscle tissue obtained from a wild individual (preserved in Traditional Chinese Medicine Resources Laboratory of Heilongjiang University of Chinese Medicine) in Yunnan, China. GenBank accession number KU180459 will be shown after the manuscript is accepted.
Organization of the complete mitochondrial genome sequence of E.carinata is shown in . Its total length is 17 154 bp. It consists of 13 protein-coding genes (PCGs), two rRNA genes, 22 tRNA genes, two control regions (CRI and CRII) and one putative origin of L-strand replication, which is similar to that of other reported snakes (Jang & Hwang Citation2011; Yan et al. Citation2014), especially to that of E. davidi (KM401547.1), E. schrenckii (KM888955.1), E. anomala (KM900218.1) and E. bimaculata (KM065513.1). As other vertebrates, most of these genes are coded on the heavy strand except for eight tRNA genes and ND6. The total composition is 25.2% C, 35.8% A, 27.0% T and 12.0% G with an obvious AT bias (62.8%), which is identical to that of other typical vertebrate mitogenomes (Mulcahy & Macey Citation2009; Jang & Hwang Citation2011).
Table 1. Gene organization of the complete mitochondrial genome of E. carinata.
As reported in other snakes. Except for ND2 (ATT) and COXI (GTG), the other 11 PCGs use ATG as start codon. When it comes to stop codons, eight PCGs end with the complete stop codon: TAA (ATP8, ATP6, ND4L, ND4 and ND5), TAG (ND2), AGA (COXI), AGG (ND6), while incomplete stop codons T are used in other five PCGs (ND1, ND3, COX2, COX3 and Cytb), which may be completed by posttranscriptional poly-adenylation (Boore Citation2001).
The mitogenome of E. carinata contains two CRs, surrounded by tRNA-Pro and tRNA-Phe (CRI), and by tRNA-Ile and tRNA-Leu (CRII), respectively. CRI has 1017 bp and CRII has 1042 bp in length, which is identical to that of other typical vertebrate mitogenomes (Li et al. Citation2014; Liu et al. Citation2015a, Citation2015b). The 22 tRNA genes are interspersed along the whole genome. The sequence length of the 12S rRNA and 16S rRNA are 927 and 1483 bp, respectively. The putative origin of L-strand replication (OL) is 35 bp in length, located between tRNA-Asn and tRNA-Cys, which is similar to most vertebrates (Su et al. Citation2007; Liu et al. Citation2015a, Citation2015b).
A phylogenetic tree () of mitochondrial genomes analyses of 16 species snakes of Colubridae was made based on the NJ method, E. carinata has the most closely relationship with E. davidi and formed a monophyletic group with E. davidi, E. schrenckii, E. anomala and E.bimaculata, meanwhile E. poryphyracea and Euprepiophis perlacea are special species.
Figure 1. Phylogenetic tree of mitochondrial genomes analyses of 16 species snakes of Colubridae based on the NJ method.
We hoped that this firstly sequenced and analysis of mitochondrial genome of E. carinata will be conducive to further studies on population genetics, molecular phylogeny and pharmacy of this species.
Acknowledgements
Chang-hong Ding is in postdoctoral mobile station in the Chinese medicine direction of Heilongjiang University Of Chinese Medicine.
Disclosure statement
The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.
Funding information
This work was supported by the National Natural Science Foundation of China (Grant No.30930700); Science and Technology Research Project of Heilongjiang Province (12531019); Research Foundation of Heilongjiang University Of Chinese Medicine (31158).
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