日本血吸虫中国大陆株基因多态性研究

对日本血吸虫中国大陆株湖南、湖北、江西、安徽、四川、云南隔离群以及一个实验室传代品系从基因水平进行了多态性研究。首先，在用ＰＣＲ－ＳＳＷＣＰ技术分析了２８Ｓ ｒＤＮＡ－Ｄ２高变区基础上，测定了该区安徽和云南隔离群的ＤＮＡ序列；其次，用ＰＣＲ获得了含有ＩＴＳ的ｒＤＮＡ片段，并对其进行了酶切点重复序列的多态性分析；最后，用ＲＡＰＤ技术分析了全基因组ＤＮＡ的多态性。结果表明，安徽与云南隔离群的２８Ｓ ｒ

Received July 19, 1999; revision received January 17, 2000

In order to analyze the interspecies diversity and the extent of diversityamong Schistosoma japonicum Chinese mainland strains, the genetic variation on genelevel among 6 isolates collected from Jiangxi, Hunan, Hubei, Anhui, Sichuan, Yunnanand a cultured isolate from a laboratory were studied using molecular biologicaltechnique. There were only two different bases at position 112 and 143 in 536bpsequence of 28S rDNA-D2 domain between Anhui and Yunnan isolates, thehomology was 99.6%. The result could be explained the reason of why the migrationrates of single chain 28S rDNA-D2 domain among the above 7 isolates were thesame completely in PCR-SSCP. However, comparing with the sequences of thePhilippine isolate of S japonicum, S mansoni and S aematobium, there were 6, 94and 93 different bases and the homologies were 98.9, 82.5 and 82.7 Per centseparately. With 8 restriction endonucleases to analyze the ITS of rDNA obtained byPCR from the 7 isolates, the results showed that only 3 minor bands were different,e.g. 5.3% of total 58 fragments. It was suggested that the ITS of rDNA among 7isolates were highly conserved. Using randomly amplified polymorphic DNA (RAPD)to analyze the genetic diversity of the genomes of the 7 isolates, the average geneticdistance (D) calculated from total 284 amplified fragments was 0.22. The maximum Dwas 0.30 and existed between Anhui and Yunnan isolates. The minimum D was 0.13and existed between Sichuan and Yunnan isolates. The clustering analysis of geneticdistances showed that the 7 isolates could be gathered in one group. From abovethree results, it could be considered that the genetic diversity on gene level amongS japonicum Chinese mainland strains was very low.