A comparison of the genetic diversity in Dipteronia sinensis Oliv. and Dipteronia dyeriana Henry |
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Authors: | Li Shan Qian Zengqiang Cai Yuliang and Zhao Guifang |
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Institution: | (1) Biodiversity Research Center of Qinling Mts, College of Life Science, Northwest University, Xi’an, 710069, China;(2) Institute of Bioresource and Applied Technology, School of Life Sciences and Technology, Tongji University, Shanghai, 200092, China |
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Abstract: | Dipteronia is an endemic genus to China and includes only two species, Dipteronia sinensis and D. dyeriana. Based on random amplified polymorphic DNA (RAPD) markers, a comparative study of the genetic diversity and genetic structure
of Dipteronia was performed. In total, 128 and 103 loci were detected in 17 D. sinensis populations and 4 D. dyeriana populations, respectively, using 18 random primers. These results showed that the proportions of polymorphic loci for the
two species were 92.97% and 81.55%, respectively, indicating that the genetic diversity of D. sinensis was higher than that of D. dyeriana. Analysis, based on similarity coefficients, Shannon diversity index and Nei gene diversity index, also confirmed this result. AMOVA analysis demonstrated that the genetic variation of D. sinensis within and among populations accounted for 56.89% and 43.11% of the total variation, respectively, and that of D. dyeriana was 57.86% and 42.14%, respectively. The Shannon diversity index and Nei gene diversity index showed similar results. The abovementioned characteristics indicated that the genetic diversity levels
of these two species were extremely similar and that the interpopulational genetic differentiation within both species was
relatively high. Analysis of the genetic distance among populations also supported this conclusion. Low levels of interpopulational
gene flow within both species were believed to be among the leading causes for the above-mentioned phenomenon. The correlation
analysis between genetic and geographical distances showed the existence of a remarkably significant correlation between the
genetic distance and the longitudinal difference among populations of D. sinensis (p < 0.01), while no significant correlation was found between genetic and geographical distances among populations of D. dyeriana. This indicated that genetic distance was correlated with geographical distances on a large scale rather than on a small
scale. This result may be related to differences in the selection pressure on species by their habitats with different distribution
ranges. We suggest that in situ conservation efforts should focus on establishing more sites to protect the natural populations and their habitats. Ex situ conservation efforts should focus on enhancing the exchange of seeds and seedlings among populations to facilitate gene exchange
and recombination, and to help conserve genetic diversity.
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Translated from Acta Phytoecologica Sinica, 2005, 29(5): 785–792 译自: 植物生态学报, 2005, 29(5): 785–792] |
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Keywords: | Dipteronia sinensis Oliv Dipteronia dyeriana Henry RAPD genetic diversity comparison |
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