Comparative Mitogenomic Analysis of Heptageniid Mayflies (Insecta: Ephemeroptera): Conserved Intergenic Spacer and tRNA Gene Duplication

• Main Authors: Ran Li, Zhiming Lei, Wenjuan Li, Wei Zhang, Changfa Zhou
• Format: Article
• Language: English
• Published: MDPI AG 2021-02-01
• Series: Insects
• Subjects: Ephemeroptera; Heptageniidae; mitochondrial genome; intergenic spacer; gene rearrangement
• Online Access: https://www.mdpi.com/2075-4450/12/2/170

Large intergenic spacers and tRNA gene duplications have been reported in several insect groups, although little is known about mitogenomes of mayflies. Here, we determined complete mitogenomes of ten heptageniid species and systemically analyzed their mitogenomic features. Both a conserved intergenic spacer (IGS) and <i>trnM</i> duplication were detected in those mitogenomes. The IGS, which was observed in heptageniids, could be further folded into a stable stem–loop structure. The tRNA gene duplication was found in almost all analyzed mitogenomes, and a unique gene block <i>trnI</i>-<i>trnM</i>-<i>trnQ</i>-<i>trnM</i>-<i>ND2</i> was also discovered. Our analysis demonstrates that the heptageniid gene arrangement pattern can be explained by the tandem duplication-random loss (TDRL) model. Phylogenetic analyses using both Bayesian inference (BI) and maximum likelihood (ML) methods based on the nucleotide and amino acid sequence data recovered the genus <i>Epeorus</i> as monophyletic with strong support. Our results provide a better understanding of mitogenomic evolution in Heptageniidae, as well as novel molecular markers for species identification of mayflies.