title: Phylogenetic Location of the Spirometra Sparganum Isolates from China, Based on Sequences of 28S rDNA D1.
abstract: BACKGROUND
  The phylogenetic location of Chinese Spirometra sparganum isolates remains unclear. The aim of this study was to explore the phylogenetic location of the Spirometra sparganum isolates from China.
  
  
  METHODS
  The 28S ribosomal DNA (rDNA) D1 sequences of 14 Spirometra sparganum isolates collected from thirteen locations in China were analyzed by using Neighbor-Joining (NJ), maximum parsimony (MP) and Bayesian inference (BI), respectively. To investigate the deep variance of 28S rDNA D1 region among included species, the secondary structure of 28S rDNA D1 region was also calculated using the program RNA structure.
  
  
  RESULTS
  The genus Spirometra as a monophyletic group was evidenced by two inference methods (MP and BI). All sequences within the genus Spirometra had a bulge of a cytosine residue (Bulge C) in the stem 13 of the secondary structure model of 28S rRNA D1 region. Varietal sites in sequences from all thirteen Chinese isolates were appeared in loops. In loops, adenine was the most abundant base (averagely 41.9%) followed by guanine (averagely 30.0%), and cytosine (averagely 15.1%). In stems, the average percentage of G + C (58.3%) was higher than the percentage of A + T (41.7%).
  
  
  CONCLUSIONS
  The 'Bulge C' in the stem 13 of the 28S rDNA D1 secondary structure could be as a suitable mark to identify the Spirometra species.
authors: Dept. of Parasitology, Medical College, Zhengzhou University, Zhengzhou, P. R. China.
authors: Xi
authors: X
authors: Zhang
authors: Dept. of Parasitology, Medical College, Zhengzhou University, Zhengzhou, P. R. China.
authors: Jing
authors: J
authors: Cui
authors: Dept. of Parasitology, Medical College, Zhengzhou University, Zhengzhou, P. R. China.
authors: Li Na
authors: LN
authors: Liu
authors: Dept. of Parasitology, Medical College, Zhengzhou University, Zhengzhou, P. R. China.
authors: Tong
authors: T
authors: Wei
authors: Dept. of Parasitology, Medical College, Zhengzhou University, Zhengzhou, P. R. China.
authors: Peng
authors: P
authors: Jiang
authors: Dept. of Parasitology, Medical College, Zhengzhou University, Zhengzhou, P. R. China.
authors: Zhong Quan
authors: ZQ
authors: Wang
keywords: 28S ribosomal DNA; Diphyllobothrium; Molecular phylogeny; Secondary structure; Spirometra