Genetic diversity and population structure of Rheum tanguticum (Dahuang) in China.
BACKGROUND
Wild Rheum tanguticum (Dahuang in Chinese) has becoming endangered in China. This study aims to examine the genetic structure and genetic diversity of R. tanguticum within species, and the genetic differentiation within and among populations in China.


METHODS
The variability and structure of 19 populations of R. tanguticum were investigated by their chloroplast DNA matK sequences. The genetic diversity index was calculated by Dnasp, PERMUT, and Arlequin 3.0 software, and a neighbor-joining (NJ)-tree was constructed by MEGA 5.0 software.


RESULTS
Fifteen haplotypes were obtained based on the matK sequence analysis. The mean genetic diversity within species was 0.894, and the genetic variability among populations (67.6%) was relatively higher than that within populations (13.88%) according to the AMOVA and PERMUT analyses. The NJ-tree and a pairwise difference analysis indicated geographical isolation of R. tanguticum. The gene flow among populations was 0.05, indicating a genetic drift among some populations, which was also confirmed by the NJ-tree and haplotype distributions. Furthermore, a mismatch distribution analysis revealed the molecular evolution of R. tanguticum.


CONCLUSIONS
Genetic diversity among and within populations of R. tanguticum in China was demonstrated.
School of Chinese Pharmacy, Beijing University of Chinese Medicine, No. 6 Wangjing Zhonghuan South Street, Chaoyang District, Beijing, 100102 China ; Lishui Hospital of Chinese Medicine, Zhejiang, 323000 China.
Xiaoqin
X
Zhang
School of Chinese Pharmacy, Beijing University of Chinese Medicine, No. 6 Wangjing Zhonghuan South Street, Chaoyang District, Beijing, 100102 China.
Ying
Y
Liu
School of Chinese Pharmacy, Beijing University of Chinese Medicine, No. 6 Wangjing Zhonghuan South Street, Chaoyang District, Beijing, 100102 China.
Xuan
X
Gu
School of Chinese Pharmacy, Beijing University of Chinese Medicine, No. 6 Wangjing Zhonghuan South Street, Chaoyang District, Beijing, 100102 China.
Zhengzheng
Z
Guo
School of Chinese Pharmacy, Beijing University of Chinese Medicine, No. 6 Wangjing Zhonghuan South Street, Chaoyang District, Beijing, 100102 China.
Li
L
Li
School of Chinese Pharmacy, Beijing University of Chinese Medicine, No. 6 Wangjing Zhonghuan South Street, Chaoyang District, Beijing, 100102 China.
Xiaona
X
Song
School of Chinese Pharmacy, Beijing University of Chinese Medicine, No. 6 Wangjing Zhonghuan South Street, Chaoyang District, Beijing, 100102 China.
Siqi
S
Liu
School of Chinese Pharmacy, Beijing University of Chinese Medicine, No. 6 Wangjing Zhonghuan South Street, Chaoyang District, Beijing, 100102 China.
Yimei
Y
Zang
School of Chinese Pharmacy, Beijing University of Chinese Medicine, No. 6 Wangjing Zhonghuan South Street, Chaoyang District, Beijing, 100102 China.
Yanpeng
Y
Li
School of Chinese Pharmacy, Beijing University of Chinese Medicine, No. 6 Wangjing Zhonghuan South Street, Chaoyang District, Beijing, 100102 China.
Chunsheng
C
Liu
School of Chinese Pharmacy, Beijing University of Chinese Medicine, No. 6 Wangjing Zhonghuan South Street, Chaoyang District, Beijing, 100102 China.
Shengli
S
Wei