分支分类学的一种计算方法——最小平行进化法

中国科学院大学学报

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分支分类学的一种计算方法——最小平行进化法

徐克学

收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:1993-11-18 发布日期:1993-11-18
通讯作者: 徐克学

An Algorithm for Cladistics—Method of Minimal Parallel Evolution

Xu Ke-xue

Received:1900-01-01 Revised:1900-01-01 Online:1993-11-18 Published:1993-11-18
Contact: Xu Ke-xue

摘要/Abstract

摘要：

本文是“分支分类的一种计算方法—最大同步法”一文的姐妹篇。两种方法运算过程基本相同，

不同之处乃是最小平行进化法利用平行进化的概念，首先确立两个分支单位相结合时产生平行进化

的步数，即平行进化系数的计算公式，对所有待结合分支单位间计算平行进化系数。然后根据俭约性

原理，要获得最俭约演化树谱图，应该尽可能减少平行进化，也就是说在选择结合的分支单位时，

选择平行进化系数最小者优先结合。于是建立起一种新的分支分类运算方法。两种方法的思路完全不

同，从原理上讲对某些数据，最小平行进化法优于最大同步法，但后者运算量较大。如果将两种思路

兼顾，可以得出由这两种方法相结合而产生平行同步综合法．桔梗科6个种的数据作为例子进行运算

说明。

关键词: 分支分类学, 最小平行进化法

Abstract:

The paper presented here is Concerned with the numerical cladisties. In

consideration of the fact that the parallel evolution has close relation to the length

of evolution graph, a new method of reconstructing evolutionary tree has been de-

veloped for the application and practice of cladistics.

The procedure of the algorithm of the new method presented in Table I is

similar to the method described in paper "An algorithm for cladistics method

of maximal same step length".

An essential step of the algorithm is how to decide the coefficient between two

cladistic units (CTUs). A coefficient called parallel evolutionary coefficient between

CTUp and CTUq is defined as follows:

where the j is code of CTU and the i is code of character; E(p, q, i, j) is a func-

tion given by following expression:

min (X_ij, Xpj)+(X_ij, Xqj)-2min(Xpj, Xqj) as Xij>min (Xpj, Xqj)

E(p,q, i,j ) =

0 otherwise.

where the X_ijis the ith row (CTU) jth colunm (Character) element of the data

matrix.

Because the method of minimal parallel evolution is closely related to the

length of evolutionary graph, it is superior to the method of maximal same step

length. A simple datum as an example for comparison shows that the method of

minimal parallel evolution can arrive at a better result.

But in some cases, we may combine one method with another and thus the

coefficient should take following form:

S(S_ij)=M·S (C)_ij-N·S(P)_ij

in which S (C)_ij and S (P)_ij are the same step coefficients and the parallel evolu-

tion coefficient respectively, and the M and N are positive integers as a weight

number being given in advance.

Key words: Cladistics, Method of minimal parallel evolution

徐克学. 分支分类学的一种计算方法——最小平行进化法[J]. 中国科学院大学学报.

Xu Ke-xue. An Algorithm for Cladistics—Method of Minimal Parallel Evolution[J]. .

分支分类学的一种计算方法——最小平行进化法

An Algorithm for Cladistics—Method of Minimal Parallel Evolution

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