The Analysis Of Aflp Markers On The Genetic Structure Of The Japanese Eel And Chinese Mitten Crab Populations

Genetic variation's size and community's genetic structure are closely related with a species' evolution potential and resistance poor surroundings' ability.The population genetic diversity levels,the forming mechanism and the space and time distribution pattern research,may reveal the species' evolution history,to analyze its evolution potential and future destiny provides the important material,will protect and uses the humanity livelihood genetic resources sustainable,saving approaches the species which will exterminate,protecting the threatened species.AFLP analysis was conducted on the two populations of Anguilla japonica from Chinese East Sea(the adult eels whose seeds came from Minjiang River and the glass eels from the Changjiang River).In order to investigate the genetic diversity and the genetic structure of the populations,56 individuals were assessed.Using 6 selective amplify primers,363 discernible DNA fragments loci were distinguished.Of these 228 were polymorphic loci(Minjiang drainage),while 269 were polymorphic loci (Changjiang drainage).The adult eel population was lower than the glass eel population(polymorphic frequencies were 62.81%,74.10%.Nei's index of phenotypic diversity were 0.2781,0.3077,Shannon index showed 0.4092,0.4493, the heterozygosity were 0.2444,0.2791).The combined results of the analysis of population genetic structure and community investigation suggested:compared with other fishes,the two East Sea eel populations had abundant genetic variation,which indicated that high levels of genetic variation existed in the natural populations of Chinese Anguilla japonica.Genetic similarity of the two populations was 0.814, genetic distance was 0.2103.According to Nei's genetic distance matrix,and the individuals of the two populations UPGMA genetic clusters were constructed.It showed that there was a high level of genetic differentiation between the two populations,which were discrepant with panmixia theory.This is the first genetic structure research on Anguilla japonica of Chinese East Sea,and it exhibit primary analysis on their diversity.Based on the ecological and genetic information available results,some explains were brought forward.The biochemical genetics in two populations of Eriocheir sinensis collected from Changjiang river's offshore were analyzed by AFLP(amplified fragments length polymorphism).One population was in the spawning migration and from Zhenjiang Dantu,the other was in feeding migration.54 individuals were assessed using 5 selective amplify primers,270 discernible DNA fragments loci were produced.Of these 235 were polymorphic loci(Changjiang river's offshore),while 269 were polymorphic loci(Zhenjiang Dantu).The result shows that the two populations genetic viability are similar.The mean effective number of alleles in loci(1.5765,1.6214).Nei's index of phenotypic diversity were 0.3523,0.3341,Shannon index 0.5148,0.4937 suggest the genetic differentiation in Zhenjiang is a litter higher than the Changing River's offshore population.The numerical results are so approximate to each other that it is hard to identification.Although the two populations are spread a certain distance,the character of migration make the same water system's population have a chance of gene communication.So the polarizations between the two populations are not so obviously.All these results shows that under the present natural environments eriocheir sinensis suffering fishing operation,pollution and other human factorshave become little influence that is to say they maintain the original genetic structures.This research using the AFLP technology to the Chinese East China Sea Anguilla japonica,the Changjiang River system eriocheir sinensis' population genetic structure carries on the analysis for the first time,and appraises their present biological resources condition.So it is helpful to clearly understand the present stage of the above species living resources condition,and provide basis of solution for the management department.Extrapolating and grasping the speciesin and between populations' genetic variation provide reference to the research of populations' differentiation.