Chinese Bulletin of Botany ›› 2011, Vol. 46 ›› Issue (2): 162-169.DOI: 10.3724/SP.J.1259.2011.00162

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Polymorphism of the Internal Transcribed Spacer of rDNA in Camellia——an Escape from Concerted Evolution

Ying Xu1, Jing Xu1,3, Jiyin Gao2,4, Wenju Zhang1*   

  1. 1Key Laboratory for Biodiversity Science and Ecological Engineering, Ministry of Education, Institute of Biodiversity Science,School of Life Sciences, Fudan University, Shanghai 200433, China;

    2Guangdong Palm Landscape Architecture ResearchInstitute, Zhongshan 528416, China;

    3Shanghai Information Center for Life Sciences, Chinese Academy of Sciences,Shanghai 200031, China;

    4Subtropical Forestry Research Institute, Chinese Academy of Forestry Sciences, Fuyang 311400, China
  • Received:2010-09-17 Revised:2010-12-17 Online:2011-03-01 Published:2011-05-09
  • Contact: Wenju Zhang

Abstract: In this study, we used 3 pairs of simple sequence repeat (SSR) markers from the 45S rDNA internal transcribed spacer (ITS) for PCR amplification in 40 species of Camellia to detect polymorphism in Camellia and the relationship between ploidy and polymorphism of species. In total, 37 species (92.5%) exhibited length polymorphism within individuals. At least 2–6 types of the ITS copies were found in individuals of these species, which indicates that non-concerted evolution is common in the ITS fragments in Camellia. Extensive non-concerted evolution may have resulted from SSR loci, which slip easily in the ITS region, and multiple rDNA loci that are located on different chromosomes. However, we did not find a significant difference in polymorphism between polyploidy and diploid. The polymorphism of the ITS region in Camellia species shows that there may be a more complex model of evolution in the rDNA of the genus, so the ITS sequences should be used with caution in solving the systematics problems of the genus.

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