Scientists at the University of Munich have shown that the properties of polymer molecules, such as proteins and DNA, allow them to enter into the process of natural selection during prebiotic (chemical) evolution. As a result, non-random chains of molecules arise. This is reported in an article published in the journal Proceedings of the National Academy of Sciences.
During the experiment, the researchers used a mixture of short chains (oligomers) of DNA, consisting of complementary bases of thymine and adenine. According to the hypothesis, in the process of attaching oligomers with random nucleotide sequences to each other, longer chains with a higher chain order are formed. Scientists analyzed the resulting sequences and confirmed that the degree of randomness in them decreased.
The reason for the spontaneous ordering was that only those chains in which the ratio of thymine to adenine is 30 to 70 (or vice versa) can arise, and chains with an equal ratio of two bases are practically not formed. In this case, motives often arise – certain combinations of bases present in different chains. Thus, there are limitations on which two-base chains can arise from chemical reactions. This contradicts the idea that there can be an unlimited number of different base combinations in a chain.
The results show that even in a simplified model system, various mechanisms of chemical selection can be implemented that affect the synthesis of polymers.