Biodiversity Data Journal :
Research Article
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Corresponding author: Kuo-Hsiang Hung (khhung424@npust.edu.tw)
Academic editor: Ricardo Moratelli
Received: 13 Nov 2021 | Accepted: 21 Dec 2021 | Published: 29 Dec 2021
© 2021 Nick Sun, Chi-Chun Huang, Yu-Wei Tseng, Tulshi Laxmi Suwal, Meng-Jou Chi, Nian-Hong Jang-Liaw, Kuo-Hsiang Hung
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Sun NC-M, Huang C-C, Tseng Y-W, Laxmi Suwal T, Chi M-J, Jang-Liaw N-H, Hung K-H (2021) Complete mitochondrial genome of Manis pentadactyla pentadactyla (Mammalia: Pholidota), an endemic subspecies of Chinese pangolin: mitogenome characterisation and phylogenetic implications. Biodiversity Data Journal 9: e77961. https://doi.org/10.3897/BDJ.9.e77961
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The Chinese pangolin Manis pentadactyla is critically endangered because of over-exploitation and illegal trafficking and includes three subspecies. However, the taxonomic status of the three subspecies of the Chinese pangolin has not been well resolved, which impedes regional conservation and illegal trade traces. In this study, the complete mitogenome sequence of M. p. pentadactyla, an endemic subspecies of the Chinese pangolin in Taiwan, was determined. The complete mitogenome of M. p. pentadactyla is 16,570 base pairs (bp) in length with 13 protein-coding genes (PCG), 23 transfer RNAs (tRNAs), two ribosomal RNAs and a 1164 bp control region. The overall base composition of the genome showed a slight A + T bias (59.9%), positive AT skew (0.1515) and negative GC skew (-0.3406), which is similar to that of other pangolins. All PCGs started with a typical ATN codon and all tRNAs were typical cloverleaf-shaped secondary structures, except for tRNA-Ser(GCU). Phylogenetic analysis indicated a monophyletic relationship for M. p. pentadactyla and M. p. aurita and was monophyletic for M. p. pentadactyla, but paraphyletic for M. p. aurita. The paraphyly of M. p. aurita resulted from an incomplete lineage sorting. This study enriched the mitogenome database of the Chinese pangolin and the molecular information obtained should be very useful for future research on mitogenome evolution and genetic diversification in M. pentadactyla.
critically endangered, Manis pentadactyla, mitogenome, phylogeny
Pangolins (Mammalia: Pholidota) are scaly-bodied mammals that inhabit a wide range of ecosystems, including secondary subtropical rainforests, bamboo forests, broadleaf forests, savanna woodlands, grasslands and agricultural landscapes in Africa and Asia (
The Chinese pangolin Manis pentadactyla Linnaeus, 1758 (Mammalia: Pholidota), is widely found in East Asia, northern Southeast Asia and parts of South Asia, including Nepal, North India, Bhutan, Bangladesh, Myanmar and the northern Indochinese Peninsula, throughout most regions to the south of the Yangtze River in China and the Islands of Hainan and Taiwan (
Three subspecies of the Chinese pangolin have been identified in some reports based on morphological traits (
An increase in pangolin numbers has been documented in many areas throughout Taiwan (
The sample of M. p. pentadactyla was obtained from eastern Taiwan (
Before genome sequencing, the quality/quantity of DNA samples were assessed using the Agilent Genomic DNA ScreenTape assay in conjunction with the 4200 TapeStation system (Agilent Technologies). The 10 ug of total DNA was sonicated using a Covaris M220 Focused-ultrasonicator to a size ranging from 400 to 500 bp. Subsequently, genomic DNA was used for library preparation using the Illumina Truseq DNA Sample Preparation Kit (Illumina, San Diego, USA), following the manufacturers’ preparation protocol. Genome sequencing was performed using the Illumina HiSeq platform for PE 2 × 150 bp sequencing. The raw sequences were filtered to obtain qualified reads using FASTP v.0.20 (
The assembled mitochondrial genome was annotated using the MITOS2 web server to predict the location of protein-coding genes (PCGs), transfer RNAs (tRNAs), ribosomal RNAs (rRNAs) and putative secondary structures of tRNAs (http://mitos2.bioinf.uni-leipzig.de/index.py) (
Phylogenetic relationships were constructed based on the full mitogenome and 13 PCG sequences of M. p. pentadactyla, M. p. aurita and other seven closely related pangolins (Suppl. material
The mitogenome sequence of M. p. pentadactyla was 16,570 bp in length and contained 22 tRNAs, two rRNAs and 13 PCGs (Fig.
Characteristics of the mitochondrial genome of Manis pentadactyla pentadactyla.
Gene |
Position |
Length (bp) |
Anticodon |
Codon |
Intergenic nucleotides* |
Strand |
||
From |
To |
Start |
Stop |
|||||
tRNA-Phe |
1 |
68 |
68 |
GAA |
0 |
H |
||
12S ribosomal RNA |
69 |
1028 |
960 |
0 |
H |
|||
tRNA-Val |
1028 |
1093 |
66 |
UAC |
-1 |
H |
||
16S ribosomal RNA |
1094 |
2659 |
1566 |
0 |
H |
|||
tRNA-Leu (UAA) |
2660 |
2733 |
74 |
UAA |
0 |
H |
||
ND1 |
2737 |
3693 |
957 |
ATG |
TAA |
3 |
H |
|
tRNA-Ile |
3693 |
3761 |
69 |
GAU |
-1 |
H |
||
tRNA-Gln |
3759 |
3831 |
73 |
UUG |
-3 |
L |
||
tRNA-Met |
3833 |
3901 |
69 |
CAU |
1 |
H |
||
ND2 |
3875 |
4913 |
1039 |
ATG |
T-- |
-27 |
H |
|
tRNA-Trp |
4941 |
5007 |
67 |
UCA |
27 |
H |
||
tRNA-Ala |
5011 |
5079 |
69 |
UGC |
3 |
L |
||
tRNA-Asn |
5081 |
5153 |
73 |
GUU |
1 |
L |
||
tRNA-Cys |
5186 |
5250 |
65 |
GCA |
32 |
L |
||
tRNA-Tyr |
5251 |
5317 |
67 |
GUA |
0 |
L |
||
COX1 |
5319 |
6869 |
1551 |
ATG |
AGA |
1 |
H |
|
tRNA-Ser(UGA) |
6865 |
6933 |
69 |
UGA |
-5 |
L |
||
tRNA-Asp |
6941 |
7007 |
67 |
GUC |
7 |
H |
||
COX2 |
7008 |
7691 |
684 |
ATG |
TAA |
0 |
H |
|
tRNA-Lys |
7694 |
7757 |
64 |
UUU |
2 |
H |
||
ATP8 |
7759 |
7959 |
201 |
ATG |
TAA |
1 |
H |
|
ATP6 |
7920 |
8600 |
681 |
ATG |
TAA |
-40 |
H |
|
COX3 |
8600 |
9383 |
784 |
ATG |
T-- |
-1 |
H |
|
tRNA-Gly |
9384 |
9452 |
69 |
UCC |
0 |
H |
||
ND3 |
9453 |
9799 |
347 |
ATA |
TA- |
0 |
H |
|
tRNA-Arg |
9800 |
9866 |
67 |
UCG |
0 |
H |
||
ND4L |
9867 |
10163 |
297 |
ATG |
TAA |
0 |
H |
|
ND4 |
10157 |
11534 |
1378 |
ATG |
T-- |
-7 |
H |
|
tRNA-His |
11535 |
11602 |
68 |
GUG |
0 |
H |
||
tRNA-Ser (GCU) |
11603 |
11661 |
59 |
GCU |
0 |
H |
||
tRNA-Leu (UAG) |
11663 |
11733 |
71 |
UAG |
1 |
H |
||
ND5 |
11743 |
13554 |
1812 |
ATA |
TAA |
9 |
H |
|
ND6 |
13538 |
14062 |
525 |
ATG |
AGA |
-17 |
L |
|
tRNA-Glu |
14063 |
14131 |
69 |
UUC |
0 |
L |
||
CYTB |
14135 |
15274 |
1140 |
ATG |
AGA |
3 |
H |
|
tRNA-Thr |
15275 |
15341 |
67 |
UGU |
0 |
H |
||
tRNA-Pro |
15341 |
15407 |
67 |
UGG |
-1 |
L |
||
D_loop |
15521 |
16570 |
1049 |
113 |
H |
Notes: * The numbers of nucleotides between the given and its previous gene, negative values indicate an overlap; H indicated that the genes are transcribed on the heavy strand.
Nucleotide composition in two rRNA, 13 protein-coding genes and 22 tRNA of mitochondrial genome of Manis pentadactyla pentadactyla.
Adenine (%) |
Cytosine (%) |
Guanine (%) |
Thymine (%) |
A+T (%) |
AT skew |
GC skew |
Length (bp) |
|
ribosomal RNA |
37.92 |
21.54 |
17.74 |
22.80 |
60.72 |
0.2490 |
-0.0967 |
2,526 |
12S ribosomal RNA |
36.87 |
22.92 |
17.92 |
22.29 |
59.16 |
0.2465 |
-0.1224 |
960 |
16S ribosomal RNA |
38.57 |
20.69 |
17.62 |
23.12 |
61.69 |
0.2504 |
-0.0801 |
1,566 |
protein-coding genes |
31.84 |
29.35 |
13.28 |
25.53 |
57.37 |
0.1100 |
-0.3770 |
11,396 |
ND1 |
33.02 |
29.99 |
12.23 |
24.76 |
57.78 |
0.1430 |
-0.4207 |
957 |
ND2 |
37.63 |
30.80 |
9.14 |
22.43 |
60.06 |
0.2531 |
-0.5423 |
1,039 |
COX1 |
28.43 |
27.21 |
15.51 |
27.85 |
56.28 |
0.0103 |
-0.2739 |
1,551 |
COX2 |
32.16 |
28.95 |
13.74 |
25.15 |
57.31 |
0.1223 |
-0.3563 |
684 |
ATP8 |
38.81 |
29.85 |
7.46 |
23.88 |
62.69 |
0.2382 |
-0.6001 |
201 |
ATP6 |
33.33 |
32.89 |
10.72 |
23.06 |
56.39 |
0.1821 |
-0.5084 |
681 |
COX3 |
26.79 |
30.99 |
16.33 |
25.89 |
52.68 |
0.0171 |
-0.3098 |
784 |
ND3 |
34.29 |
31.70 |
10.95 |
23.06 |
57.35 |
0.1958 |
-0.4865 |
347 |
ND4L |
31.98 |
29.97 |
11.45 |
26.60 |
58.58 |
0.0918 |
-0.4471 |
297 |
ND4 |
33.67 |
31.57 |
11.25 |
23.51 |
57.18 |
0.1777 |
-0.4745 |
1,378 |
ND5 |
34.93 |
30.41 |
9.88 |
24.78 |
59.71 |
0.1700 |
-0.5096 |
1,812 |
ND6 |
16.38 |
8.57 |
32.57 |
42.48 |
58.86 |
-0.4434 |
0.5834 |
525 |
CYTB |
30.53 |
31.67 |
13.86 |
23.94 |
54.47 |
0.1210 |
-0.3912 |
1,140 |
transfer DNA |
36.46 |
20.94 |
15.38 |
27.22 |
63.68 |
0.1451 |
-0.1531 |
1495 |
The sequence length of 13 PCGs was 11,396 bp with base compositions of 31.84%, 29.35%, 13.28% and 25.53% for A, C, G and T, respectively (Table
All PCGs started with a typical ATN codon: four (ND1, ND2, COX1, COX2, ATP8, ATP6, COX3, ND4L, ND4, ND6 and CYTB) with ATG and two (ND3 and ND5) with ATA. The complete stop codons, TAA and AGA, were found in six genes (ND1, COX2, ATP8, ATP6, ND4L and ND5) and three genes (COX1, ND6 and CYTB), while the remaining five genes terminated with a single base T (ND2, COX3, ND4) or one base TA (ND3) (Table
The sequence lengths of 12S and 16S rRNA were 960 bp and 1,566 bp, respectively. The base composition of both rRNAs was 37.92% A, 21.54% C, 17.74% G and 22.80% T and the A + T content was 60.72%. The 22 tRNAs were interspersed in the whole mitochondrial genome, varying from 59 (tRNA-Ser(GCU)) to 73 nucleotides (tRNA-Gln and tRNA-Asn). The A + T content of these tRNAs was 63.68% and positive AT skew and negative GC skew were found (Table
The topology of phylogenetic trees, based on full mitogenome sequences, illustrated that Asian and African pangolin species were separated into two distinct monophyletic clades, consistent with previous studies (
The complete mitochondrial genome of M. p. pentadactyla was sequenced and the mitogenome sequence was 16,570 bp in size. The AT content was higher than the GC content, which is consistent with the findings of other pangolins. Maximum Likelihood phylogenetic analysis of the complete mitogenome and 13 PCGs showed that M. p. pentadactyla and all M. p. aurita were clustered in the same clade and M. p. pentadactyla was a monophyletic group, but M. p. aurita was a paraphyletic group. The complete mitogenome of M. p. pentadactyla, reported in this study, enriches the mitogenome database of the Chinese pangolin and provides useful information for the phylogeny and taxonomy of M. pentadactyla. Based on our study, to identify subspecies of the Chinese pangolins using mtDNA markers in the wildlife trade of the Chinese pangolin can still be difficult. The Chinese pangolins have a wide range of distribution, within which intraspecific divergences may occur in some regions, especially in west of Myanmar, north and northeast India, Bangladesh, Bhutan and Nepal. To clearly confirm the status of the subspecies of the Chinese pangolin and address the conservation efforts of wildlife trade, further studies are needed, especially for the subspecies (M. p. pusilla) on Hainan Island, along with greater geographic sampling of M. p. aurita and M. p. pendactyla.
The genome sequence data are available in GenBank (https://www.ncbi.nlm.nih.gov/) under accession no. MZ868226.
This work was funded by The Ministry of Science and Technology of Taiwan under Grant [109-2628-B-020 -002].
Nick Ching-Min Sun, Chi-Chun Huang, Tulshi Laxmi Suwal, Meng-Jou Chi, Nian-Hong Jang-Liaw and Kuo-Hsiang Hung designed the experiments. Nick Ching-Min Sun, Tulshi Laxmi Suwal and Meng-Jou Chi collected materials. Chi-Chun Huang and Yu-Wei Tseng performed the experiments. Nick Ching-Min Sun, Chi-Chun Huang, Yu-Wei Tseng and Kuo-Hsiang Hung analysed the data. Nick Ching-Min Sun, Chi-Chun Huang and Kuo-Hsiang Hung drafted the manuscript.
No potential conflict of interest was reported by the author(s).
Characteristics of the mitochondrial genome of pangolins used in this study.