摘要：

阐明21号染色体上唐氏综合征关键区域内或附近的5个STR基因座（D21S1413、D21S1446、D21S1437、D21S1411、D21S1412）在北京地区汉族人群中的结构特征和群体遗传学数据。Chelex法提取血DNA，PCR扩增后，应用聚丙烯酰胺凝胶电泳和银染法或基因片段扫描检测法进行STR分型，测序后确定STR基因座的主型和进行等位基因的命名。结果该5个STR基因座具有简单重复序列和遗传多态性，杂合度和多态信息含量高。它为唐氏综合征的基因诊断和产前基因诊断提供理论依据，也为这些遗传标记在我国人群中进行亲子鉴定和个体识别提供概率计算依据。Abstract: To elucidate the genetic polymorphisms of five STR loci on chromosome 21 in Chinese Han population and construct a preliminary database，EDTA-blood specimens were collected from unrelated individuals in Beijing. The DNAs were extracted with Chelex method and were amplified by PCR. The PCR products were analyzed by the PAG electrophoresis or by the approach of the automated fluorescent detection. The five STR loci consist of simple repeat motif and its distributions of genotypes are agreement with Hardy–Weinberg equation. Its polymorphism information content is all over 0.50. The obtained data can not only be used as evidences for genetic diagnosis of Down Syndrome, but also for calculating the probabilities in the paternity test and individual identification.