Rapd Markers Temple, Maple Natural Genetic Structure And Genetic Differentiation Of Populations

Genetic structure and differentiation of Acer miaotaiense populations detected with RAPD markersLi Shan Supervisor: Zhao GUI'fang(School of Life Science, Biodiversity Research center of Qinling Mts., Northwest University, Xi'an, 710069)Acer miaotaiense is endangered species, individual numbers are very scarce, only distribute in Mts. Qinling and Mts. Ba, Shannxi Province and Tianshui, Gansu Province of China. The purpose of this thesis lies in revealing the genetic structure and differentiation of Acer miaotaiense populations.An modified CTAB method, which can successfully remove phenolic compound, polysaccharide and other small molecule organic compound , was used to obtain total DNA from the leaf tissues of Acer miaotaiense . The last optimized RAPD reaction system include 3ul template DNA, lu.1 Taq DNA polymerase, 3ul buffer (10 X ) , 1.5ul MgCl2(50mmol/L) , 0. 6ul dNTP(10mmol/L), 12ul primer(lOmer), 8. 9ul purity water.The genetic diversity of 39 individuals of three populations was investigated by random amplified polymorphic DNA (RAPD). Amplified by 20 random primers, 68 loci in 128 RAPD loci were polymorphic . The percentgae of polymorphic loci (PPB) was 53. 13%, in proper order the PPB were South-Qin&Bashan population >Tianshui population >North-Qinling population(42. 90%, 32.78%, 18.75%).Shannon diversity index was similar to the percentage of polymorphic loci, indicating lower genetic diversity level existed in Acer miaotaiense populations.Nei's index to estimate the genetic diversity of Acer miaotaiense and found that 58. 46% of genetic variation existed within the populations while 41. 54% of which among populations. The genetic distance between populations was varied from 0. 232 to 0. 281 because of the gene flow was restricted. A tree diagram from Ward' s cluster analysis showed that 39 individuals were clearly divided into three larger groups, the result suggested thatindividuals of the same population had similar genetic variability while the three populations were separated from each other. Frequency of sharing bands, mean Euclidean's distance and Nei's distance within population also showed that individuals of the same population had similar genetic variability. The liable reason is that the geographical isolation leads to the formation of small-population and the decline of genetic diversity within populations.The relationship between genetic variation and habitat of Acer miaotaiensevtas showed by PCA analysis based on RAPD data. The analysis showed that the ratio of the first three principle factors to total information was 83. 33%, the first is 37. 39 %, the second is 26. 30% and the third is 19. 64%.The liable reasons of endanger were: 1) There are some obstacles in the sexual reproduction. 2) The level of genetic diversity isn' t high. 3)Human disturbance is serious. In order to effectively preserve the plant it should to be done: 1) Perform in situ and ex situ protection. 2) Enlarge the effective population size though seed dissemination or vegetative reproduction. 3) Booster the propaganda and enhance the protective consciousness of citizen. It was suggested that the plasm germ were put in the plasm germ pool of the country cyroprotection.