First Description of Intergenic Sequences in Corydoradinae and Introducing the Complete Mitogenome of Hoplisoma concolor (Siluriformes: Callichthyidae).

Abstract

Background/Objectives: In this study, we report the complete mitochondrial genome sequence of Hoplisoma concolor Weitzman, 1961 (Siluriformes: Callichthyidae), a callichthyid catfish. Methods: DNA sequencing was performed to obtain its complete mitogenome using the HiSeq platform. To assess the phylogenetic relationships, maximum-likelihood and Bayesian inference phylogenetic trees were constructed using two ribosomal RNA (rRNA) genes and all protein-coding sequences (PCGs) concatenated from the H. concolor mitogenome, along with 31 other Siluriformes mitogenomes. Results: The complete mitogenome of H. concolor is 16,579 base pairs in length, with a nucleotide composition of 32.2% A, 26.0% T, 15.3% G, and 26.5% C. It contains 13 PCGs, 22 transfer RNA genes, and 2 rRNA genes. Phylogenetic analysis based on all PCGs and two rRNAs of the complete mitogenome confirms H. concolor as a sister species of H. panda within the subfamily Corydoradinae. In addition, intergenic sequences between atp6 and cox3 of 21 species of Corydoradinae provide further support for their phylogenetic relationship. Conclusions: Given the lack of detailed descriptions regarding the length and nucleotide composition of these intergenic sequences, our study contributes valuable insights into the genetic diversity and evolutionary complexity of Callichthyidae.