Study On The Genetic Diversity Of Moina Micrura In The Middle And Lower Reaches Of The Yangtze River

Diversity of environmental factors will affect the genetic structure of species,the eutrophication,the climate change,and the change of geographical pattern are the important factors that affect the evolution of zooplankton population.Moina micrura can be categorized as Moinidae.Moina.As a cosmopolitan species,M.micrura is often used as a model organism in ecological,physiological and toxicological studies.and has made a series of progress.However,there are few studies on genetic diversity and microevolution of it.In this study,the population of M.micrura was studied by using COI and 16S rDNA combined gene markers methods and also using DNAStar.DNAspV5,Mega 7,Network 5.0,Arlequin 3.5 as well as SPSS 20.0 data analysis processing software.and we also have analyzed the genetic diversity of active and dormancy population in the areas of middle and lower reaches of the Yangtze River.The purpose of this study was to investigate the effects of geographical pattern and nutrient changes on the phylogenetics of M.micrura.and to reveal the genetic mechanism of adaptation of M.micrura to the environment.Our results will provide basic data for the study of genetic differences among populations of M.micrura in different geographical areas all over the word.The main conclusions are as follows:(1)Through the total DNA extraction.PCR amplification and sequencing to obtain the M.micrura of a body of water COI and 16S rDNA gene sequences in the middle and lower reaches of the Yangtze River.Based on the phylogenetic analysis of COI and 16S rDNA combined gene markers.the population of Lake Nanhu in Wuhan citv is grouped into one clade alone.and in another clade.the three populations in Nanjing and the population of Shanghai is closer.(2)The gene flow map obtained by circos analysis showed that gene exchange was closely among the other 8 geographic populations except Lake Nanhu in Wuhan city.Population historical Dynamics analysis shows that the population of M.micrura in the middle and lower reaches of the Yangtze River has experienced an expansion process.in which the M.micrura dormancy population of Lake Hongze and Lake Nanjing Xuanwu(D=1.63776.P<0.01:D=-2.79641.P<0.02)and Tajima's test(D=2.44671.P<0.02:D=-1.88381.P<0.02)showed a siganificant deviation of the population from neutral evollution.The results of Pearson correlation analysis showed that the genetic differentiation of M.micrura in water bodies in the middle and lower reaches of the Yangtze River was consistent with the distance isolation model(r=0.499.P<0.001).(3)The genetic structure of the dormant population of M.micrura in the sediments of Lake Nanyi.Lake Junshan,and Lake Nanhu in Wuhan city was obviously different.In Lake Nanyi Population 2 was more active,evolved multiple haplotype:Lake Junshan two ancestor haplotype appeared in each sedimentary layer.and the sub-population 2 dominant position:in Lake Nanhu in Wuhan city Population 2 and 4 were more active.In Lake Nanvi.Lake Junshan,and Lake Nanhu in Wuhan city dormant population of M.micrura has undergone microscopic evolution in recent decades,Lake Nanhu in Wuhan city M.micrura dormancy population in the last 30 years the highest degree of evolution.Based on mismatch distribution map and neutral test also shows that Lake Nanhu of Wuhan city has a population expansion phenomenon.which was mainly affected by the sub-populations 1 and 3.Pearson Correlation Analysis showed significant negative correlation between nucleotide diversity(?)and total nitrogen as well as total phosphorus content in Lake Nanyi of the dormant population of M.micrura(r=-0.712.P=0.048;r=-0.716.P=0.046):haplotype diversity(Hd)in lake Junshan M.micrura dormancy population was significantly negatively correlated with total nitrogen content in sedimentary layers(r=-0.523,P=0.045);There was a sigenificant negative correlation between the Hd and the total phosphorus content in the sedimentary layer in the daphnia dormant population of Lake Nanhu in Wuhan city(r=-0.51 8.P=0.019).In conclusion,the change of geographical pattern and eutrophication of lakes will affect the genetic differentiation process of M.micrura population,and the genetic flow of dormancy populations also affects the genetic diversity of M.micrura.By means of the spatial spectrum of the population and the genetic differentiation on the time scale of the population are combined,the historical process of genetic differentiation and population evolution of M.micrura was discussed in this study.