| PrefaceTrichinosis caused by Trichinella spiralis is a kind of zoonosis which can spread among human and over 150 kinds of mammal. In the recent years, infection of T. spiralis has been rising in some provinces and regions, and this greatly affected the health of man and the development of stock raising, management of meat and foreign trade.The study in species and strains of trichinella was the premise of other deeper researches, so it was a hotspot. There were all kinds of disputes in classification of the species and strains all time. Before 1970, T. spiralis was considered as the only species, Boev(1979) deemed that there are four species ( Ts, Tna, Tne, Tp ). Dick ( 1983) considered Ts is the exclusive species, and Tna, Tne, Tp are subspecies. With the development of molecule biological technique, especially by HELP and RAPD, there were obvious progress in the study, and now most scholars consider there are seven species ( Tl, T2,T3, T4, T5, T7, T10 ) and three genotypes ( T6, T8, T9 ) in trichinella.In the recent years, by means of AFLP, RFLP, isozyme analysis, molecule hybridization, many native scholars considered there was distinct difference between pig T. spiralis and dog T. spiralis, and they were vested in two various species, and therefore there were atleast the two species in our country. But some scholars had opposite o-pinions. In addition, scholars did not agree on the effect of geographical distribution on species and strains.Random Amplified Polymorphic DNA analysis ( RAPD) is a new molecular marker developed by Welsh and William in 1990. It can be used to detect polymorphisms of genomic DNA, identify and classify species and strains in populations. For different species, space sites and amount of base sequence to match are different, so the size and a-mount of amplified products are also different. By agarose gel electro-phoresis, the complex DNA fingerprint patterns are gained, and the difference in some gene regions and even the whole genome among all the species can be analyzed. In order to know the more information of the genome, we must use more primers so that we can get more DNA fingerprint patterns to find new discrepancy. So far, there were only three correlative reports in China, they concluded that there were two kinds of T. spiralis at least, but did not also agree on the effect of geo-graphical distribution on species and strains.In order to investigate new gene regions and enlarge the detected area, we used 8 groups of single new primer and 12 groups of compound primers, so that we found new hereditary information, and according to the information we identified the three T. spiralis isolated in China, and compared their difference to confirm whether host and geographical distribution have effect on the species and strains. Besides, through clustering analysis we found out their relative relationship, and their differentiation, so we can accumulate the significative data for genotypic identification and classification of T. spiralis, and offer academic base for examination and diagnosis of trichinosis.MethodsGenomic DNA of the three geographical isolates of T. spiralis from Heilongjiang and Henan and two international standard species (T. spiralis, T. nativa) were amplified by PCR using single primer and their compound ones. The amplified products were separated on 1.2% agarose gel electrophoresis, stained with ethidium bromide, and photographed under U. V. trasillumination. The marker ( XDNA/EcoR I + Hind IE ) was used as molecular size standards. The size of random amplified DNA fragment was estimated by the Gelworks ID Intermediate software. According to the popular statistical method for RAPD, the data of our study was processed as the following : similarity indices between the detected individuals were calculated according to the Neis formula followed by cluster analysis using SPSS10.0 software.ResultDNA fingerprint patterns by single and compound primers ( P -01,P-03,P-04,P-05,P-06,P01 -P02,P03 - P04,P05 - P06, P02 -P06) were specific... |
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