[Analysis on codon usage of chloroplast genome of Eleutherococcus senticosus].

Objective: To analyze the codon usage of chloroplast genome and the influencing factor in Eleutherococcus senticosus.

Method: Codon of 52 genes, which were selected from the chloroplast genome sequence of E. senticosus, was multivariate statistical and correspondence analyzed using CodonW and SPSS software.

Result: GC content at the three position of codons by turns was 46.46%, 38.26%, 29.88%, whereas GC1 and GC2 had a significant correlation coefficient (P < 0.01). The correlation coefficient with GC12, and GC3 was 0.205 and was not significant correlated. There were 30 codons which relative synonymous codon usage was greater than 1 and 29 codons end with A and T. In the corresponding analysis, the first axis shows 10.35% variation. And there was significant correlation coefficient between ENC and GC3. The correlation coefficients with GC3 and ENC were -0.288 and 0.353, respectively. We defined 16 codons from 16 amino acids as the major preference codons in chloroplast genome of E. senticosus.

Conclusion: The third positions for all codon are preferred to ending with A and T. The codon usage bias is formed under effect of mutation and selection, as well as other factors. But the selection will have a far greater impact than others.