人类1号、X、Y染色体基因密码子偏好性研究

Study on Codon Usage Bias in the Gene of Human 1,X and Y Chromosomes

随着人类基因组计划测序工作的完成,进一步数据挖掘工作已成为新的研究热点。根据人类1号、X、Y染色体数据,通过自编的Perl程序,提取3条染色体基因的CDS序列,利用密码子偏好性的理论及生物信息学方法分析其碱基组成特点和密码子使用模式,确定了偏好密码子和最优密码子,探讨影响其密码子用法的主要因素。结果表明:1)人类1号、X、Y染色体基因偏好使用以G或C结尾的密码子;2)密码子的使用受基因长度的影响,较长的基因具有较高的表达水平和密码子使用偏性;3)基因表达水平对人类1号、X、Y染色体基因的密码子使用没有影响,暗示了这3条染色体并未承受翻译选择的压力;4)人类1号、X、Y染色体基因共有32个偏好性密码子,其中编码Arg的AGG和AGA、编码Val的GTG、编码Leu的CTG、终止密码子TAG为最优密码子。

With the accomplishment of the Human Genome Project, further data mining has gradually become the focus of current research. The author analyzed the whole genome sequence of human 1, X and Y chromosomes to study the coding sequences using a Perl script. According to the theory of eodon usage bias and the method of bioinformaties, biased eodons and optimal codons were identified, and the main influencing factors of usage of them were investigated by analyzing bases and eodons. The results showed that genes in human chromosome 1, X and Y were bias toward the synonymous eodons with G and C at the synonymous position. A strong correlation between codon usage bias and gene length was observed, the longer a gene＇s length, the higher its expression capacity. Surprisingly, the correlations between synonymous codon bias and gene expression levels were not significant, which implied that translation selection pressure had little impact on dominating eodon usage bias in highly expressed genes in humans. And all of genes in human chromosome 1, X and Y had thirty-two biased codons, whose biased strongly eodons were AGG/AGA（Arg）, GTG （Val）, CTG（Leu）, TAG.