Chinese Bulletin of Botany ›› 2015, Vol. 50 ›› Issue (2): 217-226.DOI: 10.3724/SP.J.1259.2015.00217

• EXPERIMENTAL COMMUNICATIONS • Previous Articles     Next Articles

Intragenomic Polymorphism of the Internal Transcribed Spacer Region of Ribosomal DNA in Camellia hongkongensis (Theaceae) and Species Identification

Wen Fan1, Ying Xu1, Ting Xu1, Jing Xu1, 2, Takahiro Yonezawa1, Jiyin Gao3, Wenju Zhang1, *   

  1. 1Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Institute of Biodiversity Science, School of Life Sciences, Fudan University, Shanghai 200433, China
    2Shanghai Information Center for Life Sciences, Chinese Academy of Sciences, Shanghai 200031, China
    3Guangdong Palm Landscape Architecture Research Institute, Zhongshan 528416, China
  • Received:2014-03-14 Accepted:2014-05-09 Online:2015-03-01 Published:2015-04-10
  • Contact: Zhang Wenju
  • About author:

    ? These authors contributed equally to this paper

Abstract: The internal transcribed spacer (ITS) region of ribosomal DNA has been selected as an important barcoding region in plants, but its use in Camellia species is difficult. In this study, we amplified, cloned and sequenced the ITS region of a Camellia plant from Vietnam that was similar to C. hongkongensis and obtained 74 sequences from an individual. The ITS region showed high polymorphism within the individual, and 76% of the sequences were pseudogenes. Phylogenetic analysis showed that more than half of the pseudogenes originated from a common ancestor. These older rDNA pseudogenes differentiated into at least 5 lineages after repeated gene duplication, and sequences in each lineage were similar to each other, which suggests that some pseudogenes had not been deleted but had recently undergone rapid duplication events. The high polymorphism of the ITS region within an individual in Camellia species would likely result in faulty identities when using this region as a barcode. However, by comparing the species-specific rDNA pseudogenes in C. hongkongensis, we identified the sample from Vietnam that belongs to C. hongkongensis.