title: [Studies of the genetic polymorphism of Schistosoma japonicum (Chinese mainland strains)].
abstract: In order to analyze the interspecies diversity and the extent of diversity among Schistosoma japonicum Chinese mainland strains, the genetic variation on gene level among 6 isolates collected from Jiangxi, Hunan, Hubei, Anhui, Sichuan, Yunnan and a cultured isolate from a laboratory were studied using molecular biological technique. There were only two different bases at position 112 and 143 in 536 bp sequence of 28S rDNA-D2 domain between Anhui and Yunnan isolates, the homology was 99.6%. The result could be explained the reason of why the migration rates of single chain 28S rDNA-D2 domain among the above 7 isolates were the same completely in PCR-SSCP. However, comparing with the sequences of the Philippine isolate of S. japonicum, S. mansoni and S. aematobium, there were 6, 94 and 93 different bases and the homologies were 98.9, 82.5 and 82.7 per cent separately. With 8 restriction endonucleases to analyze the ITS of rDNA obtained by PCR 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 7 isolates were highly conserved. Using randomly amplified polymorphic DNA (RAPD) to analyze the genetic diversity of the genomes of the 7 isolates, the average genetic distance (D) calculated from total 284 amplified fragments was 0.22. The maximum D was 0.30 and existed between Anhui and Yunnan isolates. The minimum D was 0.13 and existed between Sichuan and Yunnan isolates. The clustering analysis of genetic distances showed that the 7 isolates could be gathered in one group. From above three results, it could be considered that the genetic diversity on gene level among S. japonicum Chinese mainland strains was very low.
authors.affiliation: Dept. of Molecular Genetics, Institute of Genetics, CAS, Beijing, China.
authors.forename: X C
authors.initials: XC
authors.lastname: Yu
authors.forename: G L
authors.initials: GL
authors.lastname: Wu
authors.forename: Y J
authors.initials: YJ
authors.lastname: Zhang
authors.forename: Y Q
authors.initials: YQ
authors.lastname: Wu
authors.forename: C L
authors.initials: CL
authors.lastname: Zhu
authors.forename: Z H
authors.initials: ZH
authors.lastname: Zhang
authors.forename: B Y
authors.initials: BY
authors.lastname: Chen
mesh_terms: D000818:Animals; D001483:Base Sequence; D004275:DNA, Ribosomal / Q000737:chemistry; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D018807:Polymorphism, Single-Stranded Conformational; D019105:Random Amplified Polymorphic DNA Technique; D012549:Schistosoma japonicum / Q000235:genetics*
chemical_list: D004275:DNA, Ribosomal