摘要
本文在强调生物系统自身特点的基础上,针对分子进化本身所具有的模糊性,运用模糊聚类分析的原理和方法,就29种动物细胞色素c一级结构间的进化关系进行了研究,作出了相应的分子系统树并运用硬划分法对该树进行了修改。同时,与其它一些研究的结果进行了比较,讨论了在生物大分子一级结构间进行比较、分析的局限性和分子进化研究中的一些有待解决的问题。
On the basis of considering biosystem consisting some characteristics of fuzzy control system, this paper tried to make the research on 29 kinds of animal cytochrome c molecular evolution with Fuzzy Cluster Analysis (FCA) method and Construct their phylogenetic tree.In order to enhance the precision of constructing biological macromolecular phylogenetic trees by FCA method, according to the principle of three nucleotides determining one amino acid, we did the operation of the datum standardization of maximal similarity values (Am) between 20 kinds of common amino acids during the evolution. After Am values being determined, the maximal similarity values (S_(AB)) between two amino acid sequences can be obtained. Then we can construct the phylogenetic tree by FCA method, through the S_(AB) values of the sequences. To get the ideal phylogenetic tree, we also used Arbitrary Division method to improved repeatedly the obtained phylogenetic tree and finally we got the phylogenetic tree after the improvement. Comparing our result with the phylogenetic trees obtained by other methods, we can see that, they are agreement, and our getting the phylogenetic tree of cytochrome c is also very similar to that obtained by the fossil records.In view of biosystem being a fuzzy control system and the biological macromolecular evolution having some fuzzinesses at different degrees, on the one hand, using fuzzy mathematical principle and method to explore and discuss the evolutionary relationship among biological macromolecules is significant, and this method not only considered the direct relationship among these molecular sequences, but also involved the indirect relationship among them. In addition, our result also indicated that the precision of the phylogenetic tree is not lower than those obtained by other theoretical computing methods. However, on the other hand, because of biosystem non-linearity, when some linear mathematical models and methods are used in the research on molecular evolution, it will be unavoidable that we would obtained some results which are different from or are not all the same as the real conditions, Therefore, when different persons researched the evolutionary relationship among the same group of biological macromolecules with different methods or indexes, they are often to get different results, and these results are not also all the same as those from the fossil records. One of the reasons causing the condition is the nonlinear relationship to be treated as the linear relationship when the molecular evolutionary problems are studied, another reason of leading to the error is resulted from the limitations of the research based on the primary structural comparison and analysis. The results of comparing and analyzing sequences have shown that the difference among primary structures of some homologous macromolecules, such as, 5S rRNA, which is existed in the closer species in evolution, is greater than that of those far- ther species in evolution. In addition to it, theprimary structures of some species are not lone,sometimes the nuclectide or amino acid residue at a site may be varied. For example, in the cytochrome c sequence of Rattlesnake, which total number of the residues is 104, but there may be two types of amino acids occurring at 13 sites of this sequence. The same condition could be also seen in some other cytochrome c sequences. On the contrary, the sequences in some different species are all same with each other, such as, seal and elephant; pig, bovine and sheep etc.The studies indicated, in cytochrome c molecules of more than 60 species, that over 1/3 amino acid residues in the sequences are same, which is named the constant region, and other residue sites are in the variable region. However the variable region of cytochrome c belongs in the tertiary structure, so it is very difficult to describe precisely their differences at the level of the primary structure. It is well known that biological macromolecular primary structures are the fundament of their spatial structures and their specific functio
出处
《动物学报》
SCIE
CAS
CSCD
1991年第4期443-451,共9页
ACTA ZOOLOGICA SINICA
关键词
分子进化
细胞色素C
模糊聚类分析
Cytochrome c, molecular evolution, Phylogenetic tree, Fuzzy Cluster Analysis, Arbitrary Division
