Genetic Diversity Analysis By RAPD On Torreya Jackii Chun

RAPD analysis on Torreya jackii Chun was studied in this thesis.- Two parts, I . study on RAPD reaction conditions for T. jackii: II. the analysis of genetic diversity on T. jackii by RAPD, were included. Several results were concluded: Firstly, the population of T. jackii was decreasing sharply and its living area was contracting, so the percentage of genetic variance among T. jackii populations was lower than that within its population; Secondly, its genetic diversity index was relatively high; Thirdly, according to its gene flow index, the population disintegration of the species could be prevented by genetic communication among populations of the species; Finally, the similar index between the populations from Jiangshi Nature Reserve and from Xufan Reservoir was higher than that between the populations from Jiangshi Nature Reserve and from Xufanggeng, corresponding with the fact that it is nearer between Jiangshi Nature Reserve and Xufan Reservoir than that between Jiangshi Nature Reserve and Xufanggeng.Various effectors of RAPD have been studied. The optimal RAPD reaction system for T. jackii was determined. It contained 50 mmol/L KCU 10 mmol/LTris-HCl (pH9. 0), 0. 1% Triton-100 2 nmolM MgCl2 0. 6 nraolM dNTPs, 0. 75 u TagDNA polymerase 30 ng primer and about lOOnggenomic DNA in a total volume of 15 /4.18 primers that were detected polymorphism were screened from 80 random primers to amplify the genome of 66 T. jackii samples from 3 populations. These primers detected 199 reproducible fragments among which there were 173 reproducible polymorphism fragments. The data was analyzed with three softwares: TFPGA POPGENE32 and AMOVA155 which are tools for molecular analysis.The percentage of polymorphic sites at species level was 86.93%, and they were 83% 68% and 80% at population level. Nei' s gene diversity index was 0. 2479 at species level, and they were 0.2182, 0.1684 and 0.1881 at population level. The result of Shannon' s information index analysis was correspondent with the result of Nei' s gene diversity index analysis. So it was enlightened that T. jackii still had a high level of genetic diversity.The similar index between the T. jackii populations from Jiangshi Nature Reserve and Xufan Reservoir was higher than that between the populations from Jiangshi Nature Reserve and Xufanggeng. It was determined by geographical factors.The percentage of genetic variance among T. jackii populations was 30. 35%, and it was 69. 65% within T. jackii population. The result was correspondent with the resul ts of Gst and Fst analysis (the result of (7s t analysis was 0.2283, and that of Fst analysis was 0.2741). It was enlightened that the living space of the species was small and maybe still contracting.The gene flow index of the species was 1. 6899, it was suggested that the species still had the ability to recover from its danger situation through promoting the genetic communication among T. Jackii populations.