图们江水系绒螯蟹的形态差异与遗传混杂

为了研究图们江水系中华绒螯蟹的种群现状,以图们江水系绒螯蟹为研究材料,将我国黄河和辽河水系的中华绒螯蟹(Eriocheir sinensis),以及日本本土的日本绒螯蟹(Eriocheir japonicus)作为参照对象,应用三种形态多元分析方法与STRUCTURE聚类分析方法,对它们的32个外部形态性状进行分析。判别分析显示,图们江群体的判别准确率最低(83.30%);主成分分析显示图们江群体的12个差异最大的表型性状均位于中华绒螯蟹与日本绒螯蟹之间,呈现为中间类型;传统聚类显示图们江水系绒螯蟹与日本绒螯蟹的形态差异最小;STRUCTURE聚类显示,图们江有60%的个体聚入日本绒螯蟹群体,而只有10%的个体聚入中华绒螯蟹群体,其余30%个体为中华绒螯蟹与日本绒螯蟹的中间类型。形态研究结果表明,图们江水系绒螯蟹为中华绒螯蟹与日本绒螯蟹分布的重叠区与混杂区,但其形态偏向日本绒螯蟹。

Morphological differences and genetic admixture in mitten crabs in the Tumenjiang River

The Tumenjiang River is an international river linking China, the Democratic People’s Republic of Ko-rea, and Russia. However, there has been little research into the mitten crab in this river. In this study, mitten crabs were sampled in the Tumenjiang River and their morphological traits were compared with other populations of Chinese mitten crab (Eriocheir sinensis) sampled in the Yellow River and Liaohe River and with the Japanese mitten crab (Eriocheir japonicus) collected on the Japanese mainland. Thirty-two morphological traits were ex-amined with three kinds of multivariate analysis and a genetic cluster analysis. A discriminant analysis identified the lowest accuracy of discrimination among the Tumenjiang River crabs (83.30%). A principal components analysis revealed that the 12 largest differences in morphological traits in the Tumenjiang River population were betweenE. sinensisand E. japonicus. A traditional clustering analysis showed the smallest differences between the Tumenjiang River crabs and the Japanese crabs. The results of a genetic clustering analysis also revealed that 60% of the individual crabs in the Tumenjiang River clustered withE. japonicus,whereas only 10% of individuals clustered withE. sinensis, and the remaining 30% of individuals may have been an introgression type. These re-sults indicate that the mitten crab population in the Tumenjiang River comprises overlapping distributions or a genetically mixed population ofE. sinensis andE. japonicus, and that its morphological traits are closer to those ofE. japonicus than to those ofE. sinensis.