# Complete Mitochondrial Genome of Acheilognathus mengyangensis (Cypriniformes, Cyprinidae, and Acheilognathinae): Characterization and Phylogenetic Analysis

## TL;DR

This study sequenced the complete mitochondrial genome of Acheilognathus mengyangensis, a freshwater fish, to better understand its genetic makeup and evolutionary relationships.

## Contribution

The study provides the first complete mitochondrial genome of Acheilognathus mengyangensis and its phylogenetic analysis within the Acheilognathinae subfamily.

## Key findings

- The mitochondrial genome of Acheilognathus mengyangensis is 16,779 bp long with typical mitochondrial gene content.
- A. mengyangensis is most closely related to Acheilognathus chankaensis and Acheilognathus macropterus based on phylogenetic analysis.
- The genome shows strong AT bias and distinct codon preferences across protein-coding genes.

## Abstract

In this study, the mitochondrial genome data of Acheilognathus mengyangensis were subjected to a multigene tandem method to elucidate its taxonomic status. The total length of the mitochondrial genome was determined to be 16,779 bp, including 13 protein‐coding genes, 2 rRNA genes, 22 tRNA genes, and the D‐loop region. Overall, there was a strong AT bias and anti‐G bias; different protein‐coding genes exhibited different degrees of codon preference. The rest of the amino acids, with the exception of tRNASer (GCT), of the 22 tRNAs were in one form, the secondary structure was incomplete, and the remaining tRNAs folded to form the secondary structure of a typical clover. Thirteen protein‐coding genes of Acheilognathus and Rhodeus were concatenated to explore their phylogenetic relationships, with
Pseudorasbora parva
as the outgroup. The results revealed that
A. mengyangensis
,
Acheilognathus chankaensis
, and
Acheilognathus macropterus
were the most closely related. This research would supplement the Acheilognathus mitochondrial genome data, serving as a molecular basis for safeguarding species, facilitating genetic classification, and investigating Acheilognathinae phylogeny.

This study presents the first complete mitochondrial genome of Acheilognathus mengyangensis, a freshwater fish species endemic to specific regions in China. Our work elucidates its genomic structure, codon usage patterns, and phylogenetic relationships within the Acheilognathinae subfamily. The findings provide critical molecular insights into species conservation, genetic classification, and evolutionary studies, addressing gaps in the current understanding of this understudied group. By comparing
A. mengyangensis
with closely related species, we highlight its taxonomic position and evolutionary constraints, contributing to broader discussions on mitochondrial genome evolution in teleost fishes.