四种十足目甲壳动物遗传差异的RAPD分析

RANDOM AMPLIFIED POLYMORPHIC DNA(RAPD) ANALYSIS OF FOUR SPECIES IN DECAPOD

采用RAPD技术，对分类阶元不同的四种十足目甲壳动物：克氏原螯虾、汉水华溪蟹、日本绒螯蟹合浦亚种和中华绒螯蟹，进行了遗传多态性的研究。四个物种DNA库的扩增结果表明，随着亲缘关系由近变远，物种间的相似率依次减小，由56．1％下降到22．3％。用UPGMA方法作聚类分析构建出物种的系统树图，反映出四个物种对应的种、科间、科间以上遗传差异逐步增大，这与以形态标记为主的分类结果相一致。在同工酶分析难以揭示差异的两种绒螯蟹中，用RAPD分析观察到明显的种间差异。两种绒螯蟹个体的扩增图谱分析结果为，中华绒螯蟹个体间的平均相似率为56．9％，日本绒螯蟹合浦亚种个体间为661％，两种绒螯蟹个体间的平均相似率则为51.9％。日本绒螯蟹合浦亚种个体间的平均相似率显著高于中华绒螯蟹个体间的平均相似率，异种绒螯蟹个体间的平均相似率显著低于同种个体间的平均相似率．

A technique, known as random amplified polymorphic DNA, has been used in this report to analyze DNA polymorphisms in four species of Decapod. The species were Procambarus clarkii, Sinopotamon lansii, Eriocheir japonicus hepuensis and Eriocheir sinensis, which have different pairwise distance.Amplification of DNA pools from four species revealed the similarities among them decreased from 56.1% to 22.3%, as ancestral relationships became more distant,indicating that genome variation increased. The dendrogram based on a UPGMA analysis showed the gradual increase of genetic variation from inter-species to above-family, which was identical to the classic systematics. While little genetic variation between E. sinensis and E japonicus hepuensis was found by allozyme electrophoresis, RAPD revealed certain genetic variation between them.Amplification of DNA from individuals of E. sinensis and E japonicus hepuensis displayed the average similarities were 56.9% in E. sinensis, 66.1% in E. japonicus hepuensis, and 51.9% between two kinds of mitten crabs. The average similarity was significantly higher in E. japonicus hepuensis than in E. Sinensis, and that between two kinds of mitten crabs was significantly lower than in E. sinensis or in E. japonicus hepuensis.