The triplet codons across the watershed between the non-living and living matters

Three nucleotides per codon had been determined before deciphering the genetic code. However, it is still a mystery why there are three nucleotides per codon. This is a deceptively simple problem, which need first to clarify the prebiotic picture that has been in debate for decades. The triplet nature of life has been observed not only in the triplet codons but also in the universal 3-base periodicity in genome sequences. Here, a statistical picture on the prebiotic sequence evolution has been proposed by ascertaining the profound relationship between the evolution of the genetic code and the diversification of life. There are indications that the triplet nature of the genetic code is due to a mixture of the periods in the superhelical structures of bent DNAs.