一种考虑到不同物种同源大分子间的偶合关系的新的今祖法  

A NEW PRESENT-DAY ANCESTOR METHOD FOR CONSTRUCTING PHYLOGENETIC TREES TAKING ACCOUNT OF THE COINCIDENCE BETWEEN HOMOLOGOUS MOLECULES OF THE SPECIES BEING STUDIED AND OF THE REFERENCE SPECIES

作　　者：李靖炎[1] Li Jing-yan(Laboratory of Evolutionary Cell Biology,Kunming Institute of Zoology,Academia Sinica,Kunming,Yunnan)

机构地区：[1]中国科学院昆明动物研究所

出　　处：《Zoological Research》1988年第4期327-334,共8页动物学研究（英文）

摘　　要：今祖法可以在建立分子进化树时避免由于进化速率的差异而造成的误差。但是在实地应用中发现,在理论上应该存在的一些等式关系往往并不存在,而且在用不同物种的同源大分子作为参证时,往往竟会得到各不相同的结果。作者以前的分析表明,这是由于参证物种与被研究物种同源大分子之间的不同程度的偶合关系所造成的。据此作者提出了一种新方法,以DC′i_(a)i_(b)代替今祖法中所用的d'i_(a)i_(b)来进行成聚分析,在此DC′i_(a)i_(b)=d'i_(a)i_(b)-COi_(a)j-COi_(b)j(j代表参证物种),CO_(ij)则为d'_(ij)与任意选定的一个基准数之差。这样,同时也就避免了参证物种与被研究物种同源大分子之间的偶合关系所造成的混乱。For constructing phylogenetic trees from molecular sequence data,theoretically the present-day ancestor method makes corrections for unequal rates of evolution among lineages and yields the correct topology.However,in practice it was found that different topologies were often obtained when different species were used as references.The fact is contrary to the anticipation and to the principle about this method.The previous study of the author pointed out that the phenomenon was resulted from the different degrees of the coincidences between the homologous molecules of various species being studied and of the species used as references.In the light of this understanding the author proposes a new method that the matrix d’in the original method(d’i_(a)’b=di_(a)i_(b)-ri_(a)-ri_(b))is converted to matrix DC’,DC’i_(a)i_(b)=d/i_(a)i_(b)-COi a i-COi_(b)j,where j represents the molecule of the species used as reference,and various COi j display indirectly coincidences between land j.From matrix DC’simple clu-ster analysis can give same and correct topology whichsoever species in other evolutionary branches is used as reference.The establishment,principle and practical applying of the new method are descri_(b)ed.

关 键 词：分子进化 系统树 偶合 今祖法 

分 类 号：R18[医药卫生—流行病学]