Reference Work Entry

Encyclopedia of Astrobiology

pp 1501-1502

Self-Replication (Chemical)


Autocatalysis, cross-catalysis, informational molecule


Self-replication in astrobiology refers to the ability of a chemical system to make copies of itself without the need for external instructions. The emergence of self-replication is considered to be a necessary step for the origin of life.


Self-replication occurs when an informational molecule (such as a nucleic acid) directs the spontaneous synthesis of a replica of itself. Mechanisms for self-replication can be autocatalytic, where a molecule acts as a template to make a direct copy of itself, or cross-catalytic, where two or more molecules of different informational content amplify one another. Modern life forms use a complex cross-catalytic mechanism of replication that involves the participation of protein molecules that catalyze the replication of the informational polymer (nucleic acids), which are also involved in the synthesis of the catalysts themselves. Primordial life, h ...

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