进化距离与相对替代率的比较研究  

A Comparative Study of Evolutionary Distance and Relative Substitution Rate

作　　者：吕宝忠[1] 陈捷[1] 

机构地区：[1]上海市肿瘤研究所,200032

出　　处：《Acta Genetica Sinica》1992年第5期397-402,共6页

摘　　要：系统树是描述物种、人种甚至基因间亲缘关系和演化的重要工具,必须以进化距离或(相对)替代率作为重要的参数。但以哪一个参数构建的树更能反映真实的系统树呢?事实上迄今并无人对此作过认真的研究。本文以模拟数据并用方差分析法检验两个参数的异同并讨论其包含的生物学意义。研究结果表明,当氨基酸的替代率和核苷酸的替代率分别为0.18和0.13时,它们的进化距离分别为0.199和0.143。经方差分析证实,若检验的氨基酸和核苷酸最大数目均为75只时,不论以替代率或进化距离中那一个作为构树参数,拓扑树事实上几乎只有一个。这就是说,该时拓扑树可靠性很大,而且随着它们替代率的减少,则检验的氨基酸和核苷酸的数目会随之增加。但是一旦氨基酸的替代率和核苷酸的替代率超过上述数字,则两个参数构建的树在拓扑长度上是不等价的。经分析,若进化距离大致上与进化时间成线性关系的话,则应选用进化距离。用进化距离重建的系统树事实上支持中性学说;若进化距离与进化时间显著地不存在线性关系的话,则可选用替代率,该情况表明中性学说不适用,似更倾向于新达尔文主义。To construct a phylogenetic tree the alternative of two parameters-evolutionary distance or relative substitution rate-has to be applied. Which parameter is better for reconstructing the true tree? In reality nobody studied this issue in detail. The data of simulation and variance analysis presented in this paper showed that if p is less than 0.18 or π less than 0.13, there is no significant difference between evolutionary distance and relative substitution rate for tree-making; if p is larger than 0.18 or π larger than 0.13, there is a significant difference between that for tree-making. In latter case, if evolutionary distance is approximately proportional to evolutionary time, the neutral theory may be accepted and proved; and if evolutionary distance is out of proportion to evolutionary time, it probably suggests that this phenomenon should use relative substitution rate as parameter and can be explained by new-Darwinism.

关 键 词：系统树 进化距离 相对替代率 

分 类 号：Q349[生物学—遗传学]