Population Genetics Of Paramisgurnus Dabryanus In Chinabased On MtDNA And Microsatellite Markers

The Paramisgrnus dabryanus belongs to the Paramisgurnus,Cobitinae,Cypriniforms.It is an economical fish that widely distributed in southern and northern of China.In this study,in order to explore the evolutionary history and origin of P.dabryanus,the genetic diversity,phylogeny and intraspecific genetic structure within and among different populations were studied using morphological,Cyt b,CR sequence and SSRs.The main results are the follows:1、Species distribution and morphological analysis of P.dabryanusSystematic resource investigation and morphological comparative analysis of P.dabryanus were carried out.The resource survey results showed that P.dabryanus was widely distributed in most areas in China.Eleven morphological characters of 19P.dabryanus populations were analyzed by using GLM linear regression analysis,one-way ANOVA,discriminant analysis,principal component analysis and cluster analysis.The GLM linear regression analysis found that the anal-caudal fin distance(D_AC)/body length（L_B）was negatively correlated with latitude（r=-0.78）,and the caudal peduncle length(L_CP)/body length（L_B）was positively correlated with latitude（r=0.83）.The results of one-way ANOVA indicated that the morphological differences were not significant between the Songhua River and the Liaohe River;Songliao basin was characterized by a shorter total length,a longer caudal peduncle length,and a shorter anal-caudal fin distance.Discriminant analysis showed that the comprehensive correct diserimi-nation rate was 65.90%;the accuracy of the discrimination between the populations from Songliao basin and the southern populations were 100%.The principal component analysis result indicated 62.90%of the variance was explained by three major components.The first and most important component explained38.10%of the original variation and the parameters with strong positive discriminating power（load value>0.4）were body height（H_B）,body width（W_B）,caudal peduncle height(H_CP),caudal peduncle length(L_CP).The result of clustering analysis revealed two distinct clusters:the northern and the southern populations.The present study showed that there was significant difference in the morphological characteristics of P.dabryanus between the southern water system and the northern water system.2、Population genetics of P.dabryanus based on mtDNAPartial Cyt b amplified from 347 samples of P.dabryanus,while 365 specimens in the D-Loop datasets.A total of 106 Cyt b haplotypes and 55 D-Loop haplotypes were identified.Genetic diversity analysis revealed that higher genetic diversity were found in P.dabryanus from the southern river basin（Huaihe River,Yangtze River,Pearl River）compared to the genetic diversity indexes observed in the northern river basin（Songliao River,Haihe River,Yellow River）.The six river basin populations of P.dabryanus were characterized by relatively high genetic variation using mtDNA.Analysis of mtDNA sequences data indicated that lineage sorting is unlikely over a geological time-scale and evolutionary relationship is no obvious.The IBD results indicated that there was no significant correlation between geographical distance and genetic distances（Cyt b:r=0.037 P>0.05,D-Loop:r=-0.062 P>0.05）.The migration among populations originating from adjacent geographical regions among was high（2.679-61.454 Imm for CR,0.615-50.777 Imm for Cyt b）.The demographic history of6 populations of China displayed that the Yangtze River P.dabryanus experienced population rapid in the last Glacial Maximum,when the climate was slight warmer and more humid than at present.3、Population genetics of P.dabryanus based on microsatellite markersTo explore the genetic diversity,genetic structure and population history of P.dabryanus populations in six river basin,twelve microsatellite markers were to analyze.The analysis detected 150 alleles in twelve microsatellite loci.The H_Oand H_Evalues ranges from 0.049 to 0.656（mean=0.375）and 0.373 to 0.851（mean=0.572）.Positive Fis values,which indicate a heterozygote deficiency,were observed in all loci ranging from 0.079 to-0.891.The populations from northern populations（Songliao River,Haihe River and Yellow River）had a slightly lower level of genetic diversity compared to the southern populations（Huaihe River,Yangtze River and Pearl River）,while populations from Yangtze River basin were higher.AMOVA results revealed that 78.39%and 16.85%variation presented within populations and among population within groups.The Nei’s unbiased pairwise genetic distance values ranged from 0.018 to 0.185.The genetic relationship observed in the UPGMA analysis similar to PCo A analysis,which showed that two clear population genetic structure was found,which suggesting a certain degree of divergence between the southern populations（Huaihe River,Yangtze River,Pearl River basin）populations and the northern populations（Songliao River,Haihe River,Yellow River basin）.Meanwhile STRUCTURE analysis showed that the optimal value was 3,respectively,indicating the presence of three subgroups in the river basin.The histogram assignment results from K=3 showed that one subgroup was found mainly in Songliao River,Haihe River and Yellow River,and one subgroup was found in the all river basin,whereas another subgroup was found in Yangtze River and Pearl River.Significant deficient heterozygosity using the SMM model was observed in all population,and significant heterozygosity excess using the IAM model was observed in the Yangtze River.In general,the dynamic analysis of population history found that the P.dabryanus did not experience the bottleneck effect.