Characterization of the complete mitochondrial genome of Minois dryas (Lepidoptera: Nymphalidae: Satyrinae) with phylogenetic analysis

Abstract

The complete mitochondrial genome (mitogenome) of Minois dryas (Lepidoptera: Nymphalidae: Satyrinae) is determined to be 15,195 bp in length, including 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes, and 1 non-coding AT-rich region. The mitogenome includes a cox1 gene with an atypical CGA(R) start codon and five genes (cox1, cox2, nad5, nad4, nad1) exhibiting incomplete stop codons. The 385-bp AT-rich region contains the motif ATAGA followed by a 19-bp poly-T stretch and a microsatellite-like (TA)₆ element preceded by the ATTTA motif. The phylogenetic analysis indicated that M. dryas is formed a monophyletic group with other Satyrinae species.

Keywords:

• mitochondrial genome
• Nymphalidae
• Satyrinae
• Minois dryas

The subfamily Satyrinae, comprising approximately described species, is one of the most diverse groups of butterflies (Peña and Wahlberg 2008), comprising over a third of the Nymphalidae diversity and found on all continents except Antarctica (Ackery et al. 1999). Owing to their species richness and ecological diversification, taxonomy, and phylogeny, Satyrinae are still standing as a controversial issue, and need to be elucidated (Marín et al. 2011; Yang and Zhang 2015). The insect mitochondrial genome (mitogenome) is highly useful in phylogenetic relationships analysis, due to their unique features (Salvato et al. 2008; Wu et al. 2014; Timmermans et al. 2016).

Here, the complete mitogenome of Minois dryas (Satyrinae: Satyrini) is revealed based on the samples collected from Minshan District in Gansu Province, China (coordinates: E104° 03′, N34° 43′), and kept in the laboratory at −20 °C under the accession number SQH-20130722. Total genomic DNA was extracted from thorax muscle of an adult individual using the Sangon Animal Genome DNA Extraction Kit (Shanghai, China). The raw sequences were assembled and annotated using the BioEdit 7.0 (Hall 1999) and MEGA7.0 software (Kumar et al. 2016) with reference to the mitogenome of Davidina armandi (GenBank accession NC_028505).

The complete mitogenome of M. dryas (GenBank accession is MK521433) is 15,195 bp in length, containing typical insect 13 protein-coding genes (PCGs), two ribosomal RNA genes (rRNAs) and 22 transfer RNA genes (tRNAs), along with an AT-rich control region. Its gene arrangement and orientation are consistent with those of other known nymphalid mitogenomes (e.g. Wu et al. 2014; Shi et al. 2018; Lalonde and Marcus 2019). The nucleotide composition is also biased toward AT nucleotides (80.2%).

All PCGs are initiated by typical ATN, with the exception of the cox1 which uses the unusual CGA(R) as observed in other sequenced nymphalid mitogenomes (e.g. Kim et al. 2010; Shi et al. 2015). The mitogenome contains five PCGs (cox1, cox2, nad5, nad4, nad1) with single-nucleotide (T) stop codons completed by adding 3’ A residues post-transcriptionally. All tRNAs harbor the typical cloverleaf structures commonly found in insects, except for trnS1(AGN), whose dihydrouridine (DHU) arm is replaced by a simple loop. The rrnL and rrnS genes are 1339 bp and 772 bp in length, with the A + T contents of 84.5% and 85.7%, respectively. The putative AT-rich region is 385 bp long (94.0% A + T content) with several structures characteristic of lepidopteran, such as the 19-bp poly-T stretch preceded by the ATAGA motif neighboring the rrnS gene, and a microsatellite-like (AT)₆ element preceded by the ATTTA motif.

We performed a maximum-likelihood (ML) phylogenetic analysis with RAxML (version 7.2.6) using nucleotide sequences of 13 PCGs and 2 rRNAs to understand the phylogenetic relationship of M. dryas with other nymphalids (see Figure 1 for details). The phylogenetic analysis indicated that M. dryas formed a monophyletic group with other Satyrinae species, which was recovered as the sister group to Charaxinae, same as results from other recent analyses (Wu et al. 2014; Shi et al. 2015).

Figure 1. The maximum likelihood (ML) phylogenetic tree of Minois dryas and other nymphalid species. Phylogenetic reconstruction was done from a concatenated matrix of 13 protein-coding mitochondrial genes and 2 ribosomal RNA genes regions in the mitochondrial genome. The numbers beside the nodes are percentages of 1000 bootstrap values (* ≥ 85%). Alphanumeric terms indicate the GenBank accession numbers.

Disclosure statement

The authors report no conflict of interest. The authors alone are responsible for the content and writing of this paper.

Additional information

Funding

This work was supported by the Natural Science Foundation of Fujian Province, China [2017J05059 and 2018Y0074].