表达序列标签(expressed sequence tags, EST) 是从随机选择的cDNA 克隆进行单向测序获得的短的cDNA序列, 代表一个完整基因的一部分。随着生物信息学和基因定位的迅猛发展, EST已成为基因定位、基因克隆、基因表达分析的有力工具。近年来, 由于EST数据库的迅速扩张, 运用EST来克隆和定位基因, 使得新基因克隆的策略发生了革命性变革。尽管存在一些不足, 实践证明EST可大大加速新基因的发现与研究。本文将就EST技术尤其是它在新基因克隆中的应用策略作详细介绍。

Expressed sequence tags (EST) are short, randomly selected single-pass nucleotide sequence reads derived from cDNA libraries and represent a small part of a gene. Along with the development of bioinformatics and genetic localization, EST has already become a powerful tool for mapping, cloning and expression profiling of genes. Recently, because of the fast distension of EST databases, application of EST in gene mapping and cloning leads to revolutionary change in the strategies for cloning of novel genes. Despite of some insufficiencies, it has been proved that EST could promote the discovery and research of novel genes. In this article, an introduction about EST, especially EST-based strategies for cloning of novel genes will be given in details.