微卫星位点筛选方法综述

The Methods of Isolating Microsatellite Loci

微卫星标记因其丰富的多态性和共显性等特点,已得到了广泛的应用。应用微卫星标记首先需要获得微卫星位点的序列信息,用来设计引物。获得微卫星位点的方法有多种,本文综述了获得和富集微卫星位点的常用方法。最简便、最省时的方法是从公共数据库(如EMBL、Genbank、EST数据库等)或已发表的文献中查找到微卫星位点,但只限于已经有序列数据发布的物种。第二种方法是种间转移扩增,即从相近物种的数据库中查找微卫星位点,或使用已有数据发表的遗传距离相近物种的微卫星标记。第三种方法是从基因组DNA中筛选微卫星位点,其中用于富集微卫星的方法有引物法、磁珠杂交法、尼龙膜杂交法以及RAPD技术法。

Microsatellite DNA has been shown to be highly polymorphic and co dominant and therefore quite useful as a good genetic marker. However, the wide utilization of microsatellite marker is hindered by the difficulty of obtaining microsatellite loci from interesting species. Recently, many methods have been developed for the isolation of microsatellite loci. Among these methods, database searching is the most convenient method for obtaining new microsatellite loci, such as acquiring primers from published literatures. In recent years, with the increase of EST database, SSRs explored from dbEST have been used in many species. In addition, the conservation of repeat sequence and flanking regions across taxa makes it possible that microsatellite primers from one species can be used to detect polymorphism at homologous sites in related species. The last method is to exploit microsatellite loci from genomic DNA, including the traditional method of genomic library and the novel approach of enriched library such as magnetic bead hybridization and nylon membrane hybridization.