鸡Z染色体基因表达的密码子偏性

Study on the Codon Bias of Genes Expression in GGAZ

从NCBI数据库(http:∥www.ncbi.nlm.nih.gov/projects/mapview/map)下载鸡Z染色体上全部基因完整的cDNA,最终共有626个基因的CDS序列纳入统计分析.使用CodonW(1.4.2)进行密码子偏性分析,确定了CGG、AGC、UGC等26个密码子为Z染色体基因表达的"最优"密码子.对应分析表明,影响鸡Z染色体基因表达的密码子偏性的主要因素分别为GC3s、基因的表达丰度、GC含量、CDS长度及氨基酸的疏水性.鸡Z染色体基因表达的密码子用法受到了核苷酸组成偏好的显著影响,这种核苷酸组成偏好很可能是突变偏畸、固定偏畸及基因转换导致的.对于鸡这种群体有效规模较大的群体,密码子的偏性更有可能是核苷酸组成偏好及选择等因素综合作用的结果.

The total cDNA sequences were downloaded from NCBI dateset, and 626 CDS sequences were finally included in analyses. By the use of CodonW （ 1.4.2 ） , 26 eodons （ eg. CGG, AGC, UGC et al. ） were identified as optimal codons. The corresponding analyses indicted that the main factors influencing codon usage of genes in GGAZ were GC3s, expression level, GC content, CDS length as well as Hydrophobicity of amino acids. As the codon usage of genes in GGAZ was mostly influcenced by nueleotide composition, the bias of nucleotide composition is more likely due to the mutation bias, fix bias, and gene conversion. For a greater effective population size, the codon usage of chicken was most likely the combination of nucleotide composition and selection and so on.