Molecular Phylogeography Of Tridentiger Bifasciatus In The Chinese Inshore

In this study,the molecular phylogeography of Tridentiger bifasciatus in the Chinese Inshore were studied by Mitochondrial DNA and nuclear DNA markers.The phylogeographie patterns,genetic diversities and population structures of Tridentiger bifasciatus were carried out and the population dynamies of historical evolution were also reconstructed in the present studies.We discussed the role of historical and contemporary factors in shaping the pylogeographic pattern and genctic structures of estuarine fish.Main research results:1?Molecular phylogeography of Tridentiger bifasciatus were studied by Mitochondrial DNA markerThe mitochondrial control region and the cytochromeb gene sequence of 200 individuals of 200 populations were studied.1)The results of sequences analysis showed that mitochondrial control and cytochrome b had significant AT bias(A + T = 59.6%)and anti-G bias.2)Genetic diversities: The range of nucleotide diversity is between 0.00091 and 0.00908,the average nucleotide diversity is 0.00748,and the range of single-type diversity is between 0.757 and 1.000,And the average haplotype diversity was 0.988,which indicated that Tridentiger bifasciatus has high haplotype diversity and low nucleotide diversity.3)The phylogeographie patterns,genetic diversities and population structures of Tridentiger bifasciatus based on Mitochondrial DNABased on the experimental data,the NJ individual tree,the haplotype ML tree and a haplotype network map were used to analyze the phylogenetic relationship between the two populations,and we found that 15 geographical populations could be divided into two groups: A and B From the haplotype network we can speculate that the more primitive haplotypes belong to the YT population and the FD and DT populations respectively,and it is speculated that there may be two "shelters" in the glacial period,and after the last glacial period,the two regions Of the population were rapidly expanding.SAMOVA analysis was divided into four groups,among which there were strong gene flow among the five populations in the I group,that is,the regional genetic differentiation was extremely weak,and the main reason for this phenomenon was the influence of the current ocean current(Kuroshio)Kuroshio into the Bohai Bay,after the south,to enhance the Dandong,Tianjin,Qinhuangdao,Qingdao,Yantai area of gene exchange.The genetic structure of the study area,the genetic diversity,and the genetic diversity are affected by historical reasons and also influenced by the marine environment(ocean current).2?Molecular phylogeography of Tridentiger bifasciatus were studied by nuclear DNA marker1)Sequence analysis:The total length of the analysis was 896 bp,a total of 24 variable sites,the total mutation rate of 2.68%,including the parsim-info sites 22 accounted for 2.46%,singleton sites(singleton sites)2 accounted for 0.22%,a total of 24 haplotypes.The average content of each base was Adenine A 26.6%,Thymine T 24.7%,Cytosine C 20.5%,Guanine G 28.2%.A + T content of 51.3% slightly greater than the G + C content of 48.7%.2)Genetic diversities:The nucleotide diversity is in the range of 0.00000-0.00774 ± 0.00191,the average nucleotide diversity is 0.00329 ± 0.00051,and the range of single-type diversity is between 0.000 and 0.96 ± 0.059,Diversity was 0.689 ± 0.04,and the genetic diversity of Tridentiger bifasciatus was significant.3)The phylogeographie patterns,genetic diversities and population structures of Tridentiger bifasciatus based on nuclear DNANJ individual tree,haplotype ML tree and haplotype network map showed that 15 populations of geographic populations were intertwined with no obvious geographical differences.Table 3-4 shows the results.The differentiation indices of the 15 populations except QHD,YT and QD were below the moderate differentiation level,among which ZZ,RP population and other 11 populations had different genetic differentiation index of less than 0,Genetic differentiation was not significant,there was a strong gene flow,which may be that the evolution of the nuclear gene was slower.After the last glacial expansion,there was no significant differentiation between different geographical populations,and there was a difference between Yantai,Qinhuangdao,Qingdao and other populations Significant differentiation,suggesting that the three populations may be expected to expand earlier,regional differentiation time is longer,the accumulation of a part of the variation,and other populations have significant differentiation.