The complete mitochondrial genomes and phylogenetic analysis of Cryptotympana mandarina and C. recta: insights for molecular authentication and potential resource development of Cicadae Periostracum

Le résumé fourni par la source

The Cryptotympana genus represents a significant biological resource in health products and traditional medicine. C. mandarina and C. recta are commonly used as regional substitutes for the legal species of medicinal Cicadae Periostracum. To address the demand for supplementary molecular tools in resource identification and diversification, this study presents the first comparative analysis of mitochondrial genome architecture between C. mandarina and C. recta . Employing high-throughput sequencing technologies, we assembled complete circular mitogenomes of 15,574 bp ( C. mandarina ) and 15,802 bp ( C. recta ), each containing 37 canonical genes (13 protein-coding genes [PCGs], 22 tRNAs, 2 rRNAs). The two mitogenomes were highly similar in A + T bias, AT-skew, and GC-skew. Most PCGs exhibited ATN initiation codons, while all tRNAs demonstrated typical cloverleaf structures except for trnS1, which lacked the dihydrouridine arm. Notably, the sliding window, genetic distance, and Ka/Ks ratio analyses indicated that the ATP8 and ND2 genes are moderately conserved at the sequence level yet contain the highest proportions of variable sites among the 13 PCGs, suggesting they may serve as supplementary molecular markers for distinguishing between C. mandarina and C. recta . Phylogenetic reconstruction based on concatenated mitochondrial PCGs strongly supported a monophyletic relationship among 45 representative Cicada species (43 retrieved from NCBI plus the two newly sequenced), including C. atrata , the officially recognized source species of Cicadae Periostracum in the Chinese Pharmacopoeia. In conclusion, this study expands genomic resources for Cryptotympana taxonomy and provides a molecular basis for authentication, supporting the conservation and sustainable use of these medicinal insects.

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