植物分类学报

• 研究论文 • 上一篇    

李氏方法与Farris氏方法产生的分支系统树的比较

秦廷奎, 段宇   

  • 收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:1993-01-10 发布日期:1993-01-10
  • 通讯作者: 秦廷奎

Comparison of the Cladograms Produced by Li's Method and Farris' Method

Qin Ting-kui, Duan Yu   

  • Received:1900-01-01 Revised:1900-01-01 Online:1993-01-10 Published:1993-01-10
  • Contact: Qin Ting-kui

Abstract: In order to avoid producing  many equally most parsimonious trees, Li (1990)  developed  a  new  cladistic  method,  the  Median  Elimination Series (MES), to construct a single cladogram for a given data set. However, we found that Li's method can produce more than one tree if two or more taxa have the same advancement index (which is the total number of apomorphies for a taxon in a given data set), because there is no objective method to decide which taxon should be connected first and different orders of connection can produce different trees.   Li claimed that the result produced by his method did not apply the principle of simplicity (parsimony). Nevertheless, Zhang (1991) recognised that Li's meth- od actually accepted the principle of parsimony. Here we demonstrated that Li's method also can produce the minimum-length trees.   We conclude that Li's method could produce more than one tree and the tree(s) may be the minimum-length possible. However, the length of tree(s) depends on the order of connection of the taxa. The major problems in using Li's methodare discussed.

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