Analysis Of Genetic Structure Of Aristida Pennata In Gurbantongut Desert

The grass , Aristida pennata is a good sand-fixating herbage plant in Gurbantongut Desert .We collected 76 samples from 7 subpopulations.Using RAPD markers techonolgy analysed the genetic structure of populations and built up the reaction system of SSR markers of Aristida pennata, at the same time, analysed the genetic structure based on SSR markers techonolgy. The research results are as follow:(1) 11 amplifiction random primers were used to detecte 125 loci in 76 samples. The total proportion of polymorphic loci of. Aristida pennata is 96.8%, the average proportion of polymorphic loci of Aristida pennata is 45.3%. The analyses of Shannon diversity index (1,0.5151) and Nei gene diversity index(h, 0.3471) indicate that the gene variation is rich in subpopulations.The index (Gst=0.5284) presentes that 52.84% molecular variation existes among subpopulations, 47.16% existes within subpopulations. There are changes of genetic differentiation from 0.0000 to 1.0000. In addition, the gene flow of Aristida pennata populations is 0.4426, which suggests relative limited gene flow may be one of important factor influencing on the genetic structure of the species. The analyses above of genetic structure showe genetic differentiation had occurred among populations .(2) The experiment suggested that SSR primers were share in different species.The SSR action system built up in the experimentation was very stable, so it will be used deeply to study on genetics. 16 samples from 6 populations were amplified by SSR. we got Shannon diversity index (I) and Nei gene diversity index (h) are lower than those of RAPD. The index (Fst=0.8147) presents that 52.84% molecular variation existes among 16 individuals.In a word, our analyses showed the genetic diversity of Aristida pennata populations was rich and the genetic structure was complicate. Besides, the genetic differentiation also existed among subpopulations. We deduced that the limited gene flow and breeding type were important factors leading to genetic differentiation. The genetic structure of Aristida pennata populations reflected its characteristics of clone reproduction and the good adaption to the severe environments. Especially, under the condition of desert-expanding and habitant-destroying, the studying on the genetic structure of Aristida pennata populations is very important to understand the population persistence style of the grass in the Desert.