Characterization of the complete mitochondrial genome and phylogenetic analysis of Otus sunia (Strigiformes: Strigidae)

Abstract

The complete mitochondrial genome of Otus sunia was 17,835 bp in length and its overall base composition was estimated to be 31.0% for A, 23.3% for T, 32.4% for C, and 13.3% for G. It consisted of the typical structure of 13 PCGs, 2 ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and 1 control region. The phylogenetic analysis demonstrated that O. sunia was more closely related to O. scops than O. bakkamoena.

Keywords:

• Otus sunia
• mitochondrial genome
• phylogenetic analysis

Otus sunia, commonly called oriental scops owl, has been classified as a Class II nationally protected species in China (Holt et al. 2018). Therefore, it is crucial to figure out a valid conservation strategy. However, there is very little molecular information about this species, while the mitochondrial genome (mitogenome) sequence is proved to be informative and very useful for systematics and conservation biology studies (Curole and Kocher 1999). Particularly, previous studies have demonstrated that molecular markers generated from mitogenome sequence played a vital role in conservation studies and practices for protected animal species (Boore 1999; Galtier et al. 2009), for example, quick discoveries of illegal trafficking and poaching. In this study, we sequenced and annotated the complete mitochondrial genome of O. sunia first, and examined the phylogenetic position of O. sunia within Strigiformes to provide the basic data for conservation genetics.

Muscle sample of a wild female O. sunia that died of natural causes, was collected from Laojunshan National Nature Reserve, Yibin, Sichuan Province, China (104°00.99’, 28°41.98’). The specimen, at present, is stored in the Museum of Sichuan University. Primers used in this study were designed from the conservative regions on basis of the alignment of complete mitochondrial genomes available within the family Strigidae. Genomic DNA extraction, PCR amplification, sequencing, and annotation were conducted following the methods described by Zhou et al. (2017).

The complete mitochondrial genome of O. sunia has been deposited in the GenBank under the accession number of MF346692. The total length of the complete mitochondrial genome of O. sunia was 17,835 bp, containing 13 protein-coding (PCGs), 2 ribosomal RNA (rRNA), 22 transfer RNA (tRNA) genes, and 1 control region. The overall base composition was 23.3% of T, 32.4% of C, 31.0% of A, and 13.3% of G with an A + T ratio of 54.3%. The nucleotide compositions of the entire O. sunia mtDNA indicate the occurrence of more T and A than G and C (AT skew, 0.14; GC skew, −0.42). Resembling typical avian mtDNA, all the genes of O. sunia mtDNA encoded on the H-strand, apart from one PCG (ND6) and eight tRNAs (tRNA-Gln, tRNA-Ala, tRNA-Asn, tRNA-Cys, tRNA-Tyr, tRNA-Ser(UCN), tRNA-Pro, and tRNA-Glu) (Dove et al. 2008).

To explore the evolutionary status of O. sunia within the order Strigiformes, a maximum likelihood (ML) tree was constructed based on the concatenated 12 PCGs using RAxML (Stamatakis 2014) (Figure 1). Gallus gallus was used as the outgroup for tree rooting. The phylogenetic tree showed that O. sunia was more closely related to O. scops than O. bakkamoena. In conclusion, our study describes the complete mitogenome of O. sunia, and defines its phylogenetic position, which would facilitate further investigations of molecular evolution and conservation of this species.

Figure 1. Phylogenetic tree of O. sunia based on the maximum likelihood (ML) analysis of 12 concatenated mitochondrial protein-coding genes (with the exception of ND6). The bootstrap values for the ML analysis are shown on the nodes.

Acknowledgements

We are thankful to Guo Cai for collecting the specimen.

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

This study was supported by National Key Program of Research and Development, Ministry of Science and Technology [2016YFC0503200] and the National Natural Science Foundation of China [31702017].