Studies On Genetic Diversity Of Oxyeleotris Lineolata And Oxyeleotris Marmorata

O.lineolatus and O.marmoratus, commonly known as sand goby or soon hock, which is a commercially important species for inland fisheries. In order to know genetic variation, random amplified polymorphic DNA markers,mtDNA COI genes and mtDNA Cytb genes were used to analyze their genetic diversity. The major results and conc1usions were as follows:(1) RAPD marker:With purposes of knowing genetic variation, random amplified polymorphic DNA(RAPD) technique were used to analyze genetic diversity of O.lineolatus and O.marmoratus, and providing theoretical support for genetics and breeding. The results were as follows: there were total 72 RAPD primers which were scored from the 9 screened DNA fragments, of which 95.83% were polymorphic. The polymorphic loci ratio (P) of this two fisheries were 80.54% and 82.44% respectively. The average Nei′s gene diversity (H) were 0.2570and 0.2760respectively, and Shannons information indexes (Hi) were 0.3797 and 0.4105 respectively. The mean genetic differentiation (Gst) between them was 0.3022, the mean genetic distances (Dxy) were 0.3161. And these showed that the genetic relationships of O.marmoratus and O.lineolatus were farther relatively. Higher genetic diversity were existed, and higher genetic differentiations were also presented in this two fisheries. Results of the study can provide some theoretical basis for molecular marker-assisted selection breeding of Oxyeleotris.(2) mt DNA Cyt b genesComplete sequences of cytochrome b gene(cytb) were determined, compared and analyzed, the result showed that the average nucleotide composition of A G T C in the coding area were 26.74%,14.54%,27.66%,31.06%respectively. The nucleotide composition of G were lowest, while A were highest, and the nucleotide composition of A+T were higher than G+C. The homology of nuceotide sequence were 85%, from which we can know that Cyt b have a higher homology. The phyogenetic tree of 5 Eleotridae species and the Cyt b gene Rhyacichthys aspro were built by NJ method .The result showed that the genetic relationships of O.marmoratus and O.lineolatus were nearest , and a cluster branch were formed, which sequence alignment were consistent with the results in this study.(3) mt DNA COI genesComplete sequences of COI were determined, compared and analyzed, the result showed that the average nucleotide composition of A G T C in the coding area were 25.58%,17.7%,28.86%,27.87%respectively. The nucleotide composition of G were lowest, while T were highest, and the nucleotide composition of A+T were higher than G+C. The homology of nuceotide sequence were 86%,from phylogenetic tree which were constructed with the neighbor-joining method. Can be known that the the genetic relationships of O.marmoratus and Eleotris acanthopoma were nearest,while the genetic relationships of O.lineolatus and Odontobutis platycephala were nearest,which were different from the results of Cyt b genes and high homology of them,which showed the Oxyeleotris genetic relationships revealed by different gene sequences existed differences.