基因组中的简单重复序列

Simple sequence repeat in genome

简单重复序列广泛分布于原核和真核基因组.目前认为SSR主要由DNA复制时聚合酶滑 动导致链错配而形成.SSR在基因组中有其特定作用.某些细菌利用SSR获得"应急基因",以适应 环境变化.而在真核基因组中,SSR被发现可作为功能性的编码和调控元件.启动子区域的SSR在 其基因表达中起增强子作用.由于SSR具有高度多态性,所以可作为一种良好的分子标记应用于 各个领域.目前已对果蝇、线虫、酵母等模式生物做了全基因组范围的SSR探查.这些工作提供了 大量的SSR分子标记,为其更细致广泛的应用奠定了基础.该文就SSR的特征、组成、进化机制以 及功能和应用做了介绍和探讨.

Simple Sequence Repeat is ubiquitous in prokaryotic and eukaryotic genomes. These sequence elements show hypervariability among individuals, so can be used as molecular marks. Although it is widely accepted that SSR is derived by the mechanism of slip-strand misparing during replication, there are still some people hold that the unequal exchanges in homologous chromosomes recombination can also cause the formation of SSR. SSR has some potential functions in genome. Some bacteria use SSR as 'emergency gene', which can help them survive the variation of environments. In eukaryotes, SSR is find to be functional coding and regulatory elements. And SSR can work as enhancer in promoter region. Now, scientists have surveyed SSRs in the complete chromosomes/ genomes of humans, Drosophila melanogaster, Caenorhabditis elegans, Arabidopsis thaliana, and SaccharomycesCerevisiae These can be used in further studies. In this article, we make an introduction of the character, composition, evolution, function and application of SSR.