大豆基因组中的微卫星标记

MICROSATELLITE MARKERS IN THE SOYBEAN GENOME

微卫星ＤＮＡ是一种简单重复序列（ＳｉｍｐｌｅＳｅｑｕｅｎｃｅＲｅｐｅａｔ，ＳＳＲ），其核心单位由２－５个核苷酸组成，两侧一般是保守序列。由于它具有共显性，多态性高，可进行ＰＣＲ扩增分析，既简单又经济，因此是一种很有价值的分子标记。实验证明大豆的微卫星ＤＮＡ随机分布于基因组中，其核心单位主要是（ＡＴ）ｎ，（ＡＴＴ）ｎ。在人类基因组中占很大比例的（ＣＡ）ｎ则很少在大豆中出现。平均每一个微卫星座位有７－１０个等位基因，最高可达２６个。大豆的微卫星标记可扩充现有的ＲＦＬＰ图谱，广泛应用于基因型鉴定，基因和ＱＴＬ分析，分子标记辅助育种和家系分析等。

Microsatellites are simple, tandemly repeated di to penta nucleotide sequence motifs flanked by inique sequences. They are valuable as genetic markers because they are co dominat, detect high levels of allelic diversity and are easily and economically assayed by PCR. Experiments reveal that microsatellites are distributed throughout the soybean genome. The most abundant microsatellite motifs reported in soybean are (AT)n and (ATT)n, while (GA)n is most abundant in the human genome. There are 7-10 alleles at a single SSR locus, up to 26 alleles/locus. SSR markers can be expected to complement existing RFLP maps, are useful for genotype identification, gene and QTL analysis, marker assisted selection in breeding and pedigree analysis.