| 摘要 |
[Objectives] To analyze the evolutionary rates of mitochondrial protein-coding genes across five closely related species of fruit flies, thereby providing a foundation for the molecular identification of these quarantine pests. [Methods] The newly identified species Bactrocera latizona, along with its closely related species within the same subgenus, namely B. atrifemur, B. rubigina, B. thailandica, and B. tuberculata, were selected as the subjects of this study. Utilizing the complete mitochondrial genome sequences of these five fruit fly species, the Ka/Ks ratios of 13 protein-coding genes were calculated to assess their selective pressures and degrees of conservation. [Results] The mitochondrial genome lengths of the five fruit fly species ranged from 15 603 to 15 972 bp. The Ka/Ks ratios of the ND4L and ND4 genes for all species were generally elevated (values of the ND4L gene all exceeding 2), suggesting accelerated evolutionary rates. In contrast, the COX1 gene exhibited the lowest Ka/Ks ratio, indicating it is the most conserved gene among those analyzed. The majority of genes displayed Ka/Ks ratios below 1, implying they are under purifying selection. [Conclusions] Among the mitochondrial genes of five fruit fly species, COX1 is the most conserved, whereas ND4L exhibits the highest rate of evolution. These findings offer theoretical support for the development of molecular markers and the species identification of fruit flies. |
