Studies On PCR Amplification Of Mitochondrial DNA 12SrRNA Region And 16SrRNA Region Of Eriocheir Sinensis And Species Resources

Species resources on Chinese mitten-handed crab (Eriocheir sinensis) have been intimately attached attention to in aquaculture. At first, morphological research was used, and isoenzyme and RAPD (Random Amplified Polymorphic DNA) technique subsequently. These studies showed differences between different water systems from macrocosmic to microcosmic aspect.Mitochondrial DNA has been used in researches on heredity structure of animal strain and strain identification in the past few years. Chinese mitten-handed crabs from Yangtze, Liaohe and Oujiang Rivers were studied in our research. We have separated and purified Mitochondrial DNA (mtDNA) from hepatopancreas tissue, from which 12SrRNA and 16SrRNA region were amplified and sequenced. And single nucleotide polymorphisms (SNPs) were examined among individuals from the three populations. The 458bp pairs that encode the 12SrRNA region were sequenced, and the A, T, G, C contents of the sequences were 159bp (34.7%) , 177bp (38.6%), 52bp (11.4%), 70bp (15.3%) respectively. Four SNPs were examined among 15 individuals, including two transitions A--G (21bp in the third Oujiang crab and the fifth Liaohe crab) and two transvertions A--C (438bp in the second Liaohe crab and the fifth Oujiang crab). In our study, there were two mutation sites in Oujiang crabs and in Liaohe crabs respectively, but there was no mutation site in Yangtze crabs. The variation ratios of Oujiang and Liaohe rivers were 0.44%, and Yangtze's was zero. From the results, we concluded that the Yangtze populations are protected well in species resources. The 527bp pairs that encode the 16SrRNA region were sequenced, and the A, T, G, C contents of the sequences were 181bp (34.3%), 197bp (37.4%), 93bp (17.6%), 56bp (10.6%) respectively. And we discovered one transition and two transvertions among three individuals from three populationsrespectively, which were 21bp site (T--C) in Liaohe crabs, 520bp site (C--A) in Oujiang crabs, and 526bp site (G--C) in Yangtze crabs. Their variation ratios are 0.20%. According to their variation ratios, the crabs from the three rivers are still different geographic populations.The research analyzed heredity discrepancy among different geographic populations. There were no specific base mutation but rich single nucleotide polymorphisms (SNP). Our research results contribute to further work, for example, heredity and variation, identification of species and subspecies, conservation of species resources.