Senior M L, Heun M
United States Department of Agriculture, Agricultural Research Service, Raleigh, NC 27695-7620.
Genome. 1993 Oct;36(5):884-9. doi: 10.1139/g93-116.
Microsatellites, also called simple sequence repeats (SSRs), have yielded an important class of DNA markers most notable for mapping mammalian genomes. To study the occurrence of microsatellites and their inheritance in maize, a search was made of 280 maize GenBank sequences. Six SSRs were chosen and unique flanking primers were designed for polymerase chain reaction (PCR) amplification. Eight different maize inbreds were studied with these six primer pairs and a mean of 3.5 polymorphic patterns occurred within the expected size range. For five of these putative microsatellites, the segregation in a maize restriction fragment length polymorphism mapping population was analyzed. Four of the microsatellites cosegregated with the Adh1, Gpc1, Pdk1, and Tpi genes from which the primer sequences were derived. The fifth primer pair (MZEGPA1) showed segregating polymorphisms, but the products were larger than expected. To verify the existence of the original SSRs in the segregating PCR products, a CT primer, containing a CT SSR and an arbitrary leader sequence, was used to reamplify these products. The four microsatellites that cosegregated with the original gene were reamplified as anticipated, whereas a suspicious 230-bp product obtained when using the MZEGPA1 primers could not be reamplified. Based on these results it is concluded that microsatellites can be a valuable tool for maize mapping.
微卫星，也称为简单序列重复（SSRs），已产生了一类重要的DNA标记，这类标记在绘制哺乳动物基因组图谱方面最为显著。为了研究微卫星在玉米中的出现情况及其遗传方式，对280条玉米基因库序列进行了搜索。选择了6个微卫星，并设计了独特的侧翼引物用于聚合酶链反应（PCR）扩增。用这6对引物研究了8个不同的玉米自交系，在预期大小范围内平均出现了3.5种多态性模式。对于其中5个推定的微卫星，分析了它们在一个玉米限制性片段长度多态性作图群体中的分离情况。其中4个微卫星与引物序列所源自的Adh1、Gpc1、Pdk1和Tpi基因共分离。第五对引物（MZEGPA1）显示出分离多态性，但产物比预期的大。为了验证分离的PCR产物中原始微卫星的存在，使用了一个含有CT微卫星和任意前导序列的CT引物对这些产物进行重新扩增。与原始基因共分离的4个微卫星如预期那样被重新扩增，而使用MZEGPA1引物获得的一个可疑的230bp产物无法被重新扩增。基于这些结果，可以得出结论，微卫星可以成为玉米作图的一个有价值的工具。
