The complete mitochondrial genome of Anthrenus museorum (Coleoptera: Bostrichiformia: Dermestidae) from China

Abstract Dermestid beetles (Coleoptera: Bostrichiformia: Dermestidae) are important pests of various storage products and pose a potential threat to international trade. In this study, the whole mitogenome of Anthrenus museorum was first sequenced and annotated and was found to have the same gene order observed in known dermestid beetles. It comprised 13 protein-coding genes (PCGs), 22 transfer RNAs, 2 ribosomal RNAs and a control region. The typical ATN start codon was observed in all PCGs, except for ND3 (TTG), and all 13 PCGs showed three types of stop codons (TAA, TAG, and T-). Phylogenetic analysis based on the PCGs indicated that the relationships within Bostrichiformia were reconstructed, with the exception of one early emerging species of Bostrichidae that actually makes the group polyphyletic, as (Dermestidae + (Bostrichidae + Anobiidae)). Moreover, it revealed a close relationship between A. museorum and A. verbasci using maximum likelihood and Bayesian inference analysis.


Introduction
Anthrenus museorum (Linnaeus, 1761), belonging to the family Dermestidae (Vikberg 1999, Kadej et al. 2013, is a pest with strong adaptability and a wide range of harmful effects in various stores, such as animal carcasses, feathers, aquatic products, skin, and medicinal materials (Rajendran and Parveen 2005). It is also one of the primary hazardous pests in museum exhibition halls and specimen warehouses, particularly insect specimen warehouses. A. museorum is native to Europe and is globally dispersed through commercial logistics transmission (Bergh et al. 2003). However, dermestid beetles that are intercepted during quarantine at Chinese ports are similar in morphology and biological habits (Holloway and Pinninger 2020) and cannot be distinguished by morphology alone. Recently, molecular approaches have been employed for dermestid beetle identification, using a particular mitochondrial gene (Cytochrome oxidase 1 [COX1]). Currently, there are scarce molecular data regarding Dermestidae and Bostrichiformia insects in GenBank, with incomplete mitochondrial gene sequences (e.g. 12S, 16S genes). However, extensive studies have revealed that the species cannot be accurately identified using molecular fragments alone and that new genome-level molecular markers are constantly being developed and widely used in several non-model species (Brown et al. 1979;Ballard and Whitlock 2004). This is the first study to perform sequencing of the complete mitogenome of A. museorum, which is a useful tool for the accurate identification of this family and helps in the enrichment of the mitochondrial genome database.

Materials
A. museorum samples were collected from the thorax of Trypoxylus dichotomus (Linnaeus, 1771) from Huaxi District, Guiyang, Guizhou Province, China (26 25 0 N, 106 38 0 E), the samples were deposited in the animal laboratory of the Guiyang University (Yangyang Liu) under the voucher number GYU-20220220-002 ( Figure 1). The insects were caught and immediately soaked in alcohol, which resulted in sudden death and allowed DNA extraction immediately after capture. As the insects were arthropods, no ethical considerations were needed for this research.

DNA extraction
DNA was extracted from 10 individuals of A. museorum samples using TIANGEN Genomic DNA Extraction Kit (DP304) (TIANGEN Co., Beijing, China), according to the manufacturer's protocol. The concentration and purity of total DNA were assessed using a nucleic acid analyzer (NanoDrop 2000, Thermo Fisher Scientific, USA).

Sequencing, assembly, and annotation
After quality assessment, the library was constructed from a pooled DNA sample and sequencing was performed by the Berry Genomics Biotechnology company (Beijing, China). The genomic DNA samples were enzymatically disrupted to fragments of 350 bp in length using TruSeq Nano DNA HT Sample Preparation Kit (Illumina, USA). Next, they were sequenced using Illumina NovaSeq 6000 with 150-bp pairedend reads, and the raw data were processed using NGS QC toolkit (Patel and Jain 2012) (Supplementary Material, Figure  S1). Clean data were de novo assembled using Mitoz v. 2.3 software (Meng et al. 2019) (Supplementary Material, Figure  S2 and S3). Geneious R10 (settings: min overlap identity ¼ 95%, min overlap ¼ 50 bp, max gap size ¼ 20 bp, and max gaps/read ¼ 5%) and MITOS (settings: reference ¼ RefSeq 63 Metazoa, genetic code ¼ 5 invertebrate) were used to annotate assembled mitogenome (Kearse et al. 2012;Bernt et al. 2013), and corrected by downloading annotation results from mitochondrial genomes of closely related species in GenBank (Altschul et al. 1990). The annotate complete mitogenome sequence and raw data were submitted to GenBank and Sequence Read Archive, respectively. The mitogenome map of A. museorum was generated by Geneious R10 (Kearse et al. 2012).

Phylogenetic analysis
In this study, phylogenetic analyses were based on the nucleotide sequences of the 13 PCGs obtained from the mitogenomes of 22 species of Bostrichiformia and the outgroups (C. ferrugineus and C. pusillus), using the BI and ML methods (Figure 3). The phylogenetic topology results of these two methods were identical, and the phylogenetic relationships were as follows: (Anobiidae þ ((Bostrichidae þ Anobiidae) þ Dermestidae)). Apart from the position of sequence Anobiidae sp. KT696225, which emerges as basal to all other Bostrchiformia thus making the family Anobiidae polyphyletic, relationships at the family level are recovered as (Dermestidae þ (Bostrichidae þ Anobiidae)). The results of both phylogenetic trees revealed that A. museorum is more closely related to A. verbasci, and on this branch, the posterior probability of the Bayesian phylogenetic tree on this branch and the bootstrap value of the ML phylogenetic tree is 1/100, respectively.

Discussion and conclusion
The mitogenome of A. museorum. was 15,555 bp long, and the A þ T bias (73.4%) indicated the overall nucleotide composition of the genome, which was 69.5-84.9%, similar to that of other arthropods with significant variability in A þ T content (Dotson and Beard 2001). The gene order was identical to that of other known mitogenomes of dermestid beetles (Zeng et al. 2020). In addition, the ND3 (TTG) did not contain the typical ATN start codon, which is observed in the other 12 PCGs. The results showed that the topologies of the phylogenetic trees constructed using the two methods were similar, which was consistent with the traditional morphological classification (Holloway and Pinninger 2020). The results of both phylogenetic trees showed that the mitochondrial DNA of A. museorum was closely related to that of A. verbasci. Although only a few species of Dermestidae were included in this study, the results suggest that the mitogenome is useful as a genetic marker and is a feasible method for the systematic classification of Dermestidae. Further information regarding the mitogenome of Dermestidae insects is required in the future.

Data availability statement
The genome sequence data that support the findings of this study are openly available in GenBank of NCBI at [https://www.ncbi.nlm.nih.gov/] under the accession no. ON183351. The associated BioProject, SRA, and Bio-Sample numbers are PRJNA824543, SRS12541364, and SAMN27407755, and all accession numbers are activated.