几种模式生物密码对的使用和基因组进化

Codon Pair Usage and Genome Evolution for 6 Mode Species

以闪烁古生球菌、枯草杆菌、大肠杆菌、酿酒酵母、拟南芥和线虫基因组为样本,分别分析了编码序列中密码对、基因间序列中三联体对的相对模式数目随频数的分布,验证这种分布是Γ(α,β)分布.发现分布参数与基因组进化相关;另外,比较了密码对的观测值与期望值之差的分布,发现密码对的使用普遍具有偏好性,且不同的物种所偏好的密码对是不同的.

The distributions of relative mode number of codon pairs in protein coding sequences and triplet pairs in intergenic regions are analyzed in Archaeoglobus fulgidus, Bacillus subtili, Escherichia coli,Saccharomyces cerevisiae,Caenorhabditis elegans and Arabidopsis thaliana genomes. The results show that this kind of distribution is Г（α,β） distribution and its parameters α and βare relative to genome evolution. Besides,according to the comparison of the usages for codon pairs between the observed and expected frequencies of occurrence ,it is found that most of the usages for codon pairs are biased,and the preference varies among species.