Abstract: DNA and RNA exist together and they can be a pair of twin molecules. It seems that the earliest era of life origin is referred to as the“nucleic acid world”, afterwards DNA and RNA were generated separately by differentiation. In the modern life system, DNA, RNA and protein together play a decisive role, and the system is a three-horse-drawn carriage. The discovery of RNA interference shows that the change of phenotype of the gene can be controlled by RNA. The posttranscriptional processing of RNA is probably a reflection of the procedure of RNA evolution. Therefore, it is an urgent task to understand RNA again in life sciences.

Key words: Twin molecules, nucleic acid world, RNA interference, life evolution

摘要： DNA与RNA相伴而生，是一对孪生分子。生命起源最早出现可能是“核酸世界”，DNA与RNA是后来分化产生的。在当今生命系统中，DNA、RNA和蛋白质起着决定的作用，成为生命系统中的三驾马车。RNA干扰的发现表明，生物基因表型的变化是受RNA控制的。RNA转录后复杂的加工过程反映了RNA的进化历程。因此，重新认识RNA已成为当前生命科学亟待解决的问题。

关键词: 孪生分子, 核酸世界, RNA干扰, 生命的进化