基因字母表的最佳大小是多少？
What is the optimum size for the genetic alphabet?
作者信息
Szathmáry E
机构信息
Laboratory of Mathematical Biology, National Institute for Medical Research, Mill Hill, London, United Kingdom.
出版信息
Proc Natl Acad Sci U S A. 1992 Apr 1;89(7):2614-8. doi: 10.1073/pnas.89.7.2614.
An important question in biology is why the genetic alphabet is made of just two base pairs (G.C and A.T). This is particularly interesting because of the recent demonstration [Piccirilli, J. A., Krauch, T., Moroney, S. E. & Benner, S. A. (1990) Nature (London) 343, 33-37] that the alphabet can in principle be larger. It is possible to explain the size of the present genetic alphabet as a frozen character state that was an evolutionary optimum in an RNA world when nucleic acids functioned both for storing genetic information and for expressing information as enzymatically active RNA molecules--i.e., ribozymes. A previous model [Szathmáry, E. (1991) Proc. R. Soc. London Ser. B 245, 91-99] has described the principle of this approach. The present paper confirms and extends these results by showing explicitly the ways in which copying fidelity and metabolic efficiency change with the size of the genetic alphabet.
生物学中的一个重要问题是，为什么基因字母表仅由两个碱基对（G.C和A.T）组成。这一点尤其有趣，因为最近有研究表明[皮奇里利，J.A.，克劳奇，T.，莫罗尼，S.E.和本纳，S.A.（1990年）《自然》（伦敦）343卷，33 - 37页]，原则上基因字母表可以更大。有可能将当前基因字母表的规模解释为一种固定的字符状态，在RNA世界中，当核酸既用于存储遗传信息又用于作为具有酶活性的RNA分子（即核酶）来表达信息时，这是一种进化上的最优状态。之前的一个模型[萨瑟马里，E.（1991年）《伦敦皇家学会学报》B辑245卷，91 - 99页]描述了这种方法的原理。本文通过明确展示复制保真度和代谢效率随基因字母表规模变化的方式，证实并扩展了这些结果。
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