RNA World theory

Article By:

Breaker, Ronald R. Department of Molecular, Cellular and Developmental Biology; and Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University, New Haven, Connecticut.

Last reviewed:August 2020

DOI:https://doi.org/10.1036/1097-8542.591330

A theory expressing the idea that life on Earth passed through an era when biological processes were carried out predominantly by ribonucleic acids, without the involvement of deoxyribonucleic acids or proteins. The RNA World theory (or hypothesis) states that early forms of life may have relied solely on ribonucleic acids (RNAs) to store genetic information and to promote chemical reactions. These two functions—information storage and chemical catalysis—are essential for a “living” chemical system to self-replicate and could have formed the foundation for the earliest living entities on Earth. For life to reproduce successfully and persist through time, genetic information stored in the form of chemicals by a parent entity must be replicated and passed to its offspring. Moreover, this genetic information may accrue occasional mutations that allow some offspring to adapt to new or changing environments. Any molecule that permits the facile storage and replication of information has the potential to serve as genetic material. Also, any molecule that can promote chemical reactions efficiently to support the replication of genetic information has the potential to serve as a biological catalyst (Fig. 1). See also: Biochemistry; Catalysis and catalysts; Genetics; Mutation; Nucleic acid; Nucleotide; Ribonucleic acid (RNA)

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