中文摘要：

比较分析了同一四倍体小麦Langdon与5个不同粗山羊草在合成六倍体小麦前后A、B、D染色体组不同染色体上的微卫星变异,旨在通过分析异源多倍化引起的微卫星位点和序列变异以期探讨异源多倍体的进化机制。在所检测的位于A、B染色体组上各125个特异微卫星（G-SSR）标记中,分别有5个（4.0%）和6个（4.8%）位点发生变异;而在76个A/B染色体组上的表达序列标签微卫星（EST-SSR）标记中,只有2个（2.6%）发生了变异,比A、B染色体组G-SSR变异频率小,说明功能基因区的变异小于重复序列非编码区。在D染色体组上的103个G-SSR标记中,3个位点（2.9%）发生了序列变化。对表现差异的微卫星位点序列分析发现,人工合成小麦中多倍化引起的微卫星序列变异主要表现为简单序列重复单元次数的增加或减少;发生消除的微卫星序列比普通的微卫星序列更易发生不同类型的序列改变。微卫星序列在异源多倍化过程中对新物种基因组的形成可能起到重要的调节作用。

英文摘要：

Microsatellites or simple sequence repeats （SSR） are ubiquitous in organism genomes. Investigation on the SSR variations induced by allopolyploidization is useful to understand the evolution of allopolyploid. In this study, we compared SSR loci using primers specific to A, B, and D genomes in five synthesized hexaploid wheat between tetraploid wheat Langdon and five accessions of Aegilops tauschii. The results showed that 4.0% （5 out of 125） and 4.8% （6 of 125） genomic SSRs on A and B genomes exhibited variations, respectively. A low frequency （2.6%） of variations was observed in the expressed sequence tag （EST）-SSRs located on A/B genomes. This indicated that lower variation existed in functional genes than in non-coding regions, i.e. genomic SSR. In addition, 2.9% （3 of 103） genomic SSRs on D genome showed variations. Sequence analyses indicated that the length of SSRs was mainly due to the variation of the number of repeated units. The microsatellite sequences with disappearance may be more likely to be changed than the ordinary microsatellite sequences. The ubiquitous microsatellites may play an important buffering role to achieve genome stability and plasticity in polyploidy evolution.