Abstract: 【Objective】 Differential codon usage bias are prevalent in genomes of almost all species.In order to provide a basis for Camelus ferus genome research and codon optimization,the codon usage bias and influencing factors of Camelus ferus genome were analyzed.【Method】 The codon usage characteristics and influence factors of protein-coding genes of Camelus ferus genome were analyzed by various methods such as bioinformatics analysis,ENC-plot,Neutrality-plot and PR2-plot analysis.Meanwhile,the codon preferences between Camelus ferus and other species were analyzed.【Result】 The GC content was higher than AT content in the coding region of Camelus ferus genome,and the codon terminal bases were preferred to G/C.There were 29 codons with a relative synonymous codon usage (RSCU) greater than 1,of which 14 ended in C and 9 ended in G.The results of ENC-plot,Neutrality-plot and PR2-plot analysis showed that the codon usage bias were influenced by both natural selection and mutation,and the main factor was natural selection.Fiftheen optimal codons mainly ended with C or G were identified,including AUC,GGC,CUG,GUG,GCC,UCC,CCC,AGA,ACC,UAC,CAC,AGC,UUG,CAG and CGG.The codon usage bias of Camelus ferus, Camelus dromedarius and Mus musculus was relatively close.【Conclusion】 The codon usage bias in Camelus ferus genome was influenced by both natural selection and mutation,with natural selection played a greater influence.The results would provide reference and guidance for the protection and utilization of Camelus ferus genetic germplasm resources,genetic engineering and efficient expression of heterologous genes.

Key words: Camelus ferus; genetic codon; codon preference; natural selection; mutation pressure