转基因小鼠和基因突变小鼠微卫星不稳定性分析

目的 探讨微卫星在转基因和基因突变小鼠中的变化，为基因修饰和遗传突变动物的遗传检测和表型分析提供理论依据和技术手段。方法 根据文献报道，从GenBank中选取198个等位基因数量多、富含多态性的微卫星位点，以野生型动物为对照，对6种近交系遗传背景的转基因小鼠和5种自然基因突变的近交系小鼠进行微卫星多态性检测，选用1.5%琼脂糖凝胶电泳和STR扫描技术，比较分析微卫星不稳定性。结果 共有40个微卫星位点在转基因和基因突变小鼠中表现出多态性。在基因突变小鼠中，微卫星不稳定性有55.6%（10/18）是由纯合变为杂合（I型），有3个位点（16.6%，3/18）是纯合突变（II型），有5个位点同时存在2种类型的突变。但是在转基因动物中，大多数的微卫星多态性为I型突变（87.5%，28/32），只有2个位点（6.2%，2/32）是II型突变。另外有2个位点同时存在2种类型的突变。结论 基因修饰或基因突变可引起小鼠相关微卫星发生不稳定性，而且某些微卫星位点对基因改变敏感性较高。

Study on Microsatellite Instability in Transgenic Mice and Spontaneously MutatedInbred Mice

Objective To detect microsatellite instability(MSI) in transgenic(Tg) mice and spontaneously mutated (SM) inbred mice. MethodsAccording to the references, we selected198 microsatellite loci from 19 autosomes and X chromosomes of mice in GenBank. These loci are rich in polymorphic of mice. Then the comparative analysisof microsatellite DNA polymorphism in 6 Tg strain and 5 SM strain of mice and wild-typecontrol mice was conducted through PCR amplified. The analysis of microsatellite DNA polymorphism was undergone through 1.5% agarose gel electrophoresis and STR scanning. Results We found 40 microsatellite loci showed MSIafter the genetic modification compared to the wild type control mice.In the spontaneously mutated mice, 55.6% (10/18) changed from homozygous to heterozygous (type I), whereas three loci (16.6%) of these mice experienced homozygous mutations (type II). Five loci (27.8%) had both types of mutations. In the Tg animals, however, most of the CMP genotypes (87.5%, 28/32) were changed from homozygous to heterozygous mutations (type I), whereas only two loci (6.2%) of the micepossessed homozygous mutations (type II). Moreover, two loci harbored both types of mutations. Conclusion We primarily confirmed that gene-modify can result in MSI. Some microsatellite loci are more sensitive to genetically modification