Wang, Ting , Su, Yingjuan .
Using RAPD markers to detect the population genetic structure of Pseudotaxus chienii (Taxaceae), an endangered and endemic conifer in China.
PSEUDOTAXUS chienii (Taxaceae) is an endangered conifer endemic to China. In this research, 11 of its relictual populations located in Zhejiang, Jiangxi, Hunan and Guangxi Provinces were examined using RAPD markers. The degree of genetic differentiation among these populations was estimated by Bayesian approaches and several conventional methods as well. With a burn-in of 50000 iterations and sampling run of 250000 iterations from which every 50th sample is retained for posterior calculations, the estimate for θB was obtained as 0.5018 and its 95% credible interval is [0.4672, 0.5322]. The GST and ΦST values are 0.5865 and 0.5436, respectively. Interestingly, when using Shannon’s index of phenetic diversity to quantify and further partition the amount of genetic diversity, it was found that 48.39% of the total genetic diversity occurred among populations, very close to the θB estimate. Comparison with the estimates based on RAPD analyses of other conifer species indicated that a significantly high degree of genetic differentiation occurred among populations of P. chienii, possibly because: (1) its natural distribution has long been restricted in disjunct isolates characteristic of a scattered patterns; (2) the species is dioecious, tending to grow under dense canopy, which hinders the female cone from being pollinated; and (3) the sample collection covers almost the entire range of the species, a far large geographical distance. Mantel test showed that the degree of population genetic differentiation is significantly related with geographic distance (r = 0.719, P = 0.003). In addition, a low level of RAPD variation was revealed within P. chienii. It was suggested that bottleneck effects as well as the effects of genetic drift in small populations resulted in the reduction of genetic variation. In terms of the above results, the development of conservation strategies for P. chienii were discussed.
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1 - Wuhan botanical garden, Chinese Academy of Sciences, Evolutionary genetics, Moshan, Wuhan, Hubei, 430074, China
2 - Indiana University, Department of Biology, Jordan Hall, 1001 East Third Street, Bloomington, Indiana, 47405, USA
population genetic structure
Presentation Type: Oral Paper:Papers for Topics
Date: Tuesday, August 1st, 2006
Time: 4:30 PM