Genetic Differences And Diversity Of Mitten Crabs Eriocheir From Different Rivers

The genetic differences and diversity of fifteen mitten crab populations from 6 river systems in mainland China, one population from Russia and 289 individuals among them were studied based on RFLP analysis of mitochondrial cytochrome oxidase subunit I (COI), polymorphisms of mitochondrial COI gene of Eriocheir sinensis sampled from JiangDu and NanJing in ChangJiang River were specially analyzed by using RFLP and DGGE methods in this paper, due to hybridization and/or artificial transplantation for aquaculture, which resulted in mixture of Eriocheir species in natural river, heteroplasmy strains and low genetic diversity in Eriocheir sinensis. The results are following:1. In the RFLP analysis of 16 populations of mitten crabs, Tas I -RFLP pattern could be used as genetic marker to distinguish Eriocheir hepuensis from Eriocheir sinensis, Eriocheir japanica and Eriocheir leptognathus; Genetic distances among thirteen populations of Eriocheir sinensis in OuJiang, ChangJiang, Yellow River, HaiHe and LiaoHe range from 0 to 0.015, indicating that they were different geographic strains; Eriocheir leptognathus (population from NanPaihe, Tianjin) was the most distant taxon with genetic distances value of 0.147～0.195, which could be defined as genetic distances between species in Genus Eriocheir.2. In the RFLP analysis of 289 individuals among 11 populations of mitten crabs, 15 composite haplotypes were detected, while haplotype 1 was shared by all the samples except Eriocheir hepuensis and had high percentage, Eriocheir hepuensis was mainly composed of haplotype 4 and had distinct genetic differences compared with Eriocheir sinensis from Yellow River, Haihe and Liaohe (Pnet=0.060～0.061); Genetic diversity of intrapopulation existed in Eriocheir sinensis of 6 River systems, Eriocheir hepuensis and Eriocheir japonica (π=0.0002～0.0167).3. In the RFLP analysis of Eriocheir sinensis sampled from NanJing and JiangDu of ChangJiang River, when using 8 restriction endonucleases (recognizing 4 base pairs),the index of intrapopulational nucleotide diversity (πvalue) of NanJing and JiangDu, were 0.008 and 0.019 respectively, that were consistent with the result of RFLP analysis using 11 restriction endonucleases (8 recognizing 4 base pairs and 3 recognizing 6 base pairs) (0.007 and 0.016, respectively), indicating that the genetic diversity existed within the population of Eriocheir sinensis in ChangJiang River.4. DGGE method was used for analyzing the polymorphisms of mitochondrial COI gene of Eriocheir sinensis sampled from NanJing in ChangJiang River, These results indicated that more...