Schmidt T, Heslop-Harrison J S
Department of Cell Biology, John Innes Centre, Norwich, United Kingdom.
Proc Natl Acad Sci U S A. 1996 Aug 6;93(16):8761-5. doi: 10.1073/pnas.93.16.8761.
Microsatellites, tandem arrays of short (2-5 bp) nucleotide motifs, are present in high numbers in most eukaryotic genomes. We have characterized the physical distribution of microsatellites on chromosomes of sugar beet (Beta vulgaris L.). Each microsatellite sequence shows a characteristic genomic distribution and motif-dependent dispersion, with site-specific amplification on one to seven pairs of centromeres or intercalary chromosomal regions and weaker, dispersed hybridization along chromosomes. Exclusion of some microsatellites from 18S-5.8S-25S rRNA gene sites, centromeres, and intercalary sites was observed. In-gel and in situ hybridization patterns are correlated, with highly repeated restriction fragments indicating major centromeric sites of microsatellite arrays. The results have implications for genome evolution and the suitability of particular microsatellite markers for genetic mapping and genome analysis.
微卫星是短（2 - 5个碱基对）核苷酸基序的串联阵列，在大多数真核生物基因组中大量存在。我们已经对甜菜（Beta vulgaris L.）染色体上微卫星的物理分布进行了表征。每个微卫星序列都显示出特征性的基因组分布和基序依赖性分散，在一到七对着丝粒或染色体中间区域有位点特异性扩增，并且沿着染色体有较弱的、分散的杂交。观察到一些微卫星被排除在18S - 5.8S - 25S rRNA基因位点、着丝粒和中间位点之外。凝胶内杂交和原位杂交模式相关，高度重复的限制性片段表明了微卫星阵列的主要着丝粒位点。这些结果对基因组进化以及特定微卫星标记用于遗传图谱绘制和基因组分析的适用性具有重要意义。
