Zuckerkandl E
J Mol Evol. 1975 Dec 31;7(1):1-57. doi: 10.1007/BF01732178.
The likelihood of a de novo generation of classes of efficient proteins through neoformation of DNA, through modification of expressed DNA, and through modification of nonexpressed DNA is examined. So is the likelihood that newly formed inefficient enzymes be turned into efficient enzymes. The conclusions are that neither gene duplicates nor dormant genes represent promising materials for a de novo generation of protein classes, that (with exceptions) such generation is unlikely to have taken place in recent evolution, that new structural genes must nearly consistently derive from preexisting structural genes, and that new functions can be evolved only on the basis of old proteins. Conditions of protein evolution in prokaryotes suggest that the saltatory formation of protein classes is as unlikely in prokaryotes as in eukaryotes. Data on the history of a few protein classes are reviewed to illustrate the preceding inferences. The analysis leads to the hypothesis that most protein classes originated before the major elements of the translation apparatus of modern cells were fully evolved. If simple sequence DNA is turned into structural genes by evolution, this process (again with exceptions) is considered to have taken place only at that very remote period. A polyphyletic origin of proteins is thought to date back to the same era. It is proposed that the development of genic multiplicity and of marked structural and functional diversity of proteins may have come about in the earliest cells primarily through the independent generation of structurally different polymerases in different protocells, followed by cell conjugation and the subsequent use by enriched cells of supernumerary types of polymerase for evolving further functions. Functional growth, as it took place at early times, is briefly discussed as well as functional change. The foundations for new functional developments in old proteins are analyzed. In considering the evolutionary recovery of lost functions, aspects of cell differentiation and gene regulation are linked with the evolutionary picture. The distinction between eurygenic and stemogenic control of gene activity is used. Next to gene deletion, cell and tissue deletion is held to be an event of general evolutionary significance, through cell and tissue origination that presumably accompanies the restoration of a lost molecular function.
本文考察了通过DNA的新形成、已表达DNA的修饰以及未表达DNA的修饰，从头产生高效蛋白质类别的可能性。同时也考察了新形成的低效酶转变为高效酶的可能性。结论是，基因复制和休眠基因都不是从头产生蛋白质类别的有前途的材料，（少数例外情况除外）这种产生在近期进化中不太可能发生，新的结构基因几乎总是源自先前存在的结构基因，并且新功能只能在旧蛋白质的基础上进化。原核生物中蛋白质进化的条件表明，蛋白质类别的跳跃式形成在原核生物中与在真核生物中一样不太可能。回顾了一些蛋白质类别的历史数据以说明上述推论。分析得出一个假说，即大多数蛋白质类别在现代细胞翻译装置的主要元件完全进化之前就已起源。如果简单序列DNA通过进化转变为结构基因，那么这个过程（同样有少数例外情况）被认为仅在那个非常遥远的时期发生。蛋白质的多源起源被认为可追溯到同一时代。有人提出，基因多样性以及蛋白质显著的结构和功能多样性的发展，可能主要是在最早的细胞中，通过不同原始细胞中独立产生结构不同的聚合酶，随后细胞结合，以及富集细胞随后使用多余类型的聚合酶来进化出进一步的功能而实现的。还简要讨论了早期发生的功能增长以及功能变化。分析了旧蛋白质中新功能发展的基础。在考虑丧失功能的进化恢复时，将细胞分化和基因调控的方面与进化图景联系起来。使用了基因活性的泛基因控制和干细胞控制之间的区别。除了基因缺失外，细胞和组织缺失被认为是具有普遍进化意义的事件，这是通过细胞和组织的起源实现的，而这大概伴随着丧失分子功能的恢复。
