Codon Usage Pattern and its Influencing Factors for Mitochondrial CO Genes Among Different Subfamilies of Cerambycidae.

This study examined nucleotide composition and codon usage of mitochondrial CO (cytochrome oxidase) genes from four subfamilies of Cerambycidae. Nucleotide composition analysis of the CO genes revealed an AT-rich pattern in the four subfamilies of Cerambycidae. Furthermore, by analyzing the correlation between the overall nucleotide composition of CO genes and the nucleotide composition of the 3rd codon, we found that mutation pressure and natural selection were the key factors affected the CUB. The regression of GC12 (The average of GC content of the entire gene first and second codon positions) vs GC3 (GC content of the entire gene third codon positions) scattered to a limited value, and all CO genes slope of the regression line was all less than 0.5, indicated that natural selection might have played a significant role in shaping the codon usage bias. ENC plot analysis further supported the predominant influence of natural selection on CUB, aligning with the findings from neutral plot analyses. These novel insights into the codon evolution of CO genes within Cerambycidae significantly contribute to our understanding of codon evolution.