中文摘要：

目的分析弓形虫不同分离株染色体DNA多态性。方法采用PFGE技术对弓形虫8个分离株进行分子核型分析。结果在2．0～6．0Mb范围内分离出7～8条染色体，各株PFGE电泳分子核型大体相似．但部分染色体DNA电泳迁移速度并不一致并存在共迁移现象，8个分离株分为3个类型。结论弓形虫不同分离株既存在一定的同源性，但同时又显示染色体DNA多态性。这可能同弓形虫不同分离株毒力等生物特性的差异有关。

英文摘要：

To analyze the polymorphism of chromosome DNAs of Toxoplasma gondii isolates, the pulsed field gel electrophoresis （PFGE） technique was used to analyze the molecular karyotypes of chromosome DNAs of 8 Toxoplasma gondii isolates, in which 7-8 chromosome DNAs at size range from 2.0 Mb to 6.0 Mb were separated from T. gondii isolates by PFGE and the molecular haryotypes of chromosome DNAs were almost similar among various isolates of T. gondii. However, different migration speed and co-migration of the chromosome DNAs by electrophoresis separation existed in certain strains of isolates, thus making the 8 isolates to be divided into 3 different groups. It is apparent that the polymorphism in chromosome DNAs exists in T. gondii isolates, although certain degree of homology is present in some strains. This may be potentially due to the difference in biological characteristics of these isolates including their virulence.