Image courtesy of Aza Toth, public domain.
Joel Kontinen
Life uses a common set of 20 coded amino acids (CAAs) to construct proteins. This set was likely canonicalized during early evolution; before this, smaller amino acid sets were gradually expanded as new synthetic, proofreading and coding mechanisms became biologically available.
The expression, likely canonised during early evolution,is evolution speak. That is, it is not possible to make it any stronger.
This study showed that in silico hypothetical CAA sets of 3–19 amino acids comprised of 1913 structurally diverse α-amino acids, exploring the adaptive value of their combined physicochemical properties relative to those of the modern CAA set.
Thus, life came about because it was intelligently designed by God.
Source:
Ilardo, Mwlisssa et al. Adaptive Properties of the Genetically Encoded Amino Acid Alphabet Are Inherited from Its Subsets. Scientific Reports 9, Article number: 12468 (2019).