Studies On Polymorphism In The DNA Fragments Of Schistosoma Japonicum From Hunan Province

To illuminate intraspecific variation in Schistosoma japonicum from Hunan Province and thus to provide foundation for further studies of molecular genetics and molecular diagnostics.PCR amplification, cloning, sequencing and sequence analysis were used to study sequence variation in internal transcribed spacers(ITS) of ribosomal DNA (rDNA), mitochondrial NADH dehydrogenase subunit 4 (nad4) and cytochrome c oxidase subunitl (coxl) between isolates of S. japonicum from Hunan Province. Result shows: 1.The report of S.japonicum ITS sequence from Chang Sha, Yue Yang-qianlianghu, Hunan Province is the first time in China, and it is also the first report of complete SJaponicum ITS-1 in the world.Compared with SJaponicum partial ITS-1 and complete ITS-2 sequences available in the DNA database, distinct variation was found. 2.A pair of PCR primers for the amplification of partial nad4 was designed according to the nad4 sequence of SJaponicum and Fasciola hepatica available in the GenBank. The fragment of partial nad4 was approximately 500bp in length, and our report of the nad4 sequence was the first time in China. Sequence variation in nad4 among isolates from Hunan Province ranged from 1.0% to 2.9%.3. Sequencing analysis revealed that the sequence variation in coxl ranged from 0.2% to 1.2%.The results of the present studies revealed that ITS, nad4 and cox1 provide ideal genetic markers for the studies of genetic variation within SJaponicum. The results of the present studies should have important implications for studying the life-cycles, transmission patterns, epidemiology and population genetics of isolates of S. japonicum, and for the diagnosis of diseases they cause.