中文摘要：

基因的表达水平受到起始密码子下游区域AT含量的影响,从巨大的序列集中筛选出具有特定AT含量和密码子用法特征的同义序列是一个繁琐的工作。本文研发AT含量优化工具＂BestAT＂,初步解决了自动获取海量同义序列和充分展示同义序列的密码子用法特性两个关键问题,并且实现了与密码子用法数据库（CUD）的无缝结合,采用了密码子参数的原位标示和AT含量曲线等直观方式展示序列特性,为这类实验设计提供有力的支持。

英文摘要：

AT content of the initiation codon downstream region affects the expression level of a gene.Picking up synonymous sequences that have specific AT content and codon usage features from tremendous sequence set is a burdensome work.In this paper,the tool named BestAT for AT content optimization had been developed.The tool resolved two key issues,（i） auto-generating mass synonymous sequences and（ii） revealing their codon usage features in details.Moreover,the tool was closely incorporated to the Codon Usage Database（CUD）,and supported marking in situ codon parameters and showing visualized AT curve.All of those help to experimental design for AT content optimization powerfully.