Habitable Zone in Nucleotide Composition Space: Phase Diagram of Life

We plotted the whole-genome sequences of many organisms in nucleotide composition space. As a result, all genome sequences were distributed in a very narrow region in the four-dimensional nucleotide composition space of each of the first and second letters of the codon. In other words, the eight-dimensional compositional space of the first and second letters of the codon represents the habitable zone, the area where organisms can survive. A major characteristic of the habitable zone is that it deviates significantly from a completely random composition. In such cases, the number of possible DNA sequences is fiercely small, which naturally explains why the organism is in an extremely low-entropy state. Furthermore, DNA sequences that would make it impossible to design an organism are eliminated in advance, and the mutations that occur in an organism are naturally neutral. Furthermore, physical considerations have shown that the region of nucleotide composition called the habitable zone is the phase diagram of life.