Comparative Studies On Morphology And Populations Genetic Structure Among Five Populations Of Macrobrachium Nipponense

In this paper,multivariation analysis,DNA sequencing and PCR-RFLP were conducted to compare the morphological variations and genetic divergence among five populations(Guangxi Population,GX;Taihu Lake Population,TH;Huainan of Anhui Province Population,HN;Lishui of Zhejiang Province Population,LS;Cultured in Zhejiang Province Population,CP)of Macrobrachium nipponense.The results showed genetic background and relationship among the five populations.1.Studies on difference in morphology and discrimination among five populations of of M. nipponenseThe morphological variations among five populations of M.nipponense were analyzed using three multivariable analysis methods based on 16 proportional parameters of morphometric characters.The results of cluster analysis revealed that differences between population TH and HN,CP,LS were more and more.The difference between population TH and GX was the largest,and population GX formed a group alone.The identification accuracy of Stepwise Discriminant was 100%and discriminant functions of five populations were established. Principal component analysis revealed that there were 2 principal components for M.nipponense, which showed higher contribution to variance,and their cumulative contribution were 75.384% and 83.012%,respectively.PC1 represented the morphometric characters of abdomen,carapace and second periopod,and PC2 represented the motphometric characters of body,rostrum and telson.In the Distribution of five populations of M.nipponense plotted on factor(2)×factor(1) coordinate,there was much overlap among population TH,HN and LS,population CP showed some differences from those three populations,and population GX could distinguish from other four populations easily.The results of three multivariable analyses showed the morphological variation from several aspects,population GX was different from other four populations significantly in morphology.It is feasible to compare the different populations of M.nipponense and to identify their origin by the method of Stepwise Discrimination.2.Studies on genetic structure among five populations of M.nipponense The genetic structures and diversities of five populations of M.nipponense were assessed by using mtDNA COI gene fragment sequencing and PCR-RFLP of mtDNA control region.The result of COI gene fragment sequencing indicated that the genetic diversities of population GX,TH and LS were higher than those of other,and the result of PCR-RFLP showed that those of population GX,HN and LS were higher,both results revealed that population CP had the lower genetic diversity;Genetic distance showed that compared with other populations,population TH,HN and CP were closest,population LS was farther to those three populations,and population GX was farthest to those three;Dendrograms showed that population TH,HN and CP formed a group,and population GX and LS formed another;Analysis of moleculer variance (AMOVA)revealed that there was great genetic divergence among the five populations.The results of mtDNA COI gene sequencing can directly reveal the genetic variation of the species, but much expensive.Therefore,if the species do not have prior genome sequence information, PCR-RFLP of mtDNA control region is a powerful marker of choice for the assessment of genetic variation among populations.3.Compare of studies on morphology and genetic structure for five populations of M.nipponenseComparing the results of morphology and genetic structure for five populations of M.nipponense,there was only difference on the relationship between LS and other populations: population LS was close to TH group in morphology,but it was close to population GX in genetics.Both results showed that,population TH,HN and CP were close;population GX was farthest to those three populations;There was great differentiation among the five populations.