Before revision: The stability of sequence replication was crucial for the emergence of molecular evolution and early life. Exponential replication with a first-order growth dynamics show inherent instabilities such as the error catastrophe and the dominance by the fastest replicators. This favors less structured and short sequences. The theoretical concept of hypercycles has been proposed to solve these problems. Their higher-order growth kinetics leads to frequency-dependent selection and stabilizes the replication of majority molecules. However, many implementations of hypercycles are unstable or require special sequenceswith catalytic activity .
After revision: Each living species carries a complex DNA sequence that determines their unique features and functionalities. It is generally assumed that life started from a random pool of oligonucleotides sequences, generated by a prebiotic polymerization of nucleotides. The mechanism that initially facilitated the emergence of sequences that code for the function of the first species from such a random pool of sequences remains unknown. It is a central problem of the origin of life. An interesting option would be a self-selection mechanism by spontaneous symmetry breaking. Initial concentration fluctuations of specific sequence motifs would have been amplified and outcompeted less abundant sequences, enhancing the signal to noise to replicate and select functional sequences .