Individual bases : take away the sugar in the DNA backbone = no function
Take away the phosphate in the backbone = no function
Take away the nucleic acid bases = no function
Evolution is not a driving force at this stage, since replication of the cell depends on DNA.
So the individual DNA molecules are irreducible complex
DNA in general ( the double helix )
Unless the two types, purines, and pyrimidines are present, and so the individual four bases = no function, and no hability of information storage
The enzymes and proteins for assembly and synthesis of the DNA structure must also be present, otherwise, no DNA double helix......
Origin of the DNA deoxyribonucleic acid double helix
Self-organizing biochemical cycles 1
How were ribonucleotides first formed on the primitive earth? This is a very difficult problem. Stanley Miller's synthesis of the amino acids by sparking a reducing atmosphere (2) was the paradigm for prebiotic synthesis for many years, so at first, it was natural to suppose that similar methods would meet with equal success in the nucleotide field. However, nucleotides are intrinsically more complicated than amino acids, and it is by no means obvious that they can be obtained in a few simple steps under prebiotic conditions. A remarkable synthesis of adenine (3) and more or less plausible syntheses of the pyrimidine nucleoside bases (4) have been reported, but the synthesis of ribose and the regiospecific combination of the bases, ribose, and phosphate to give β-nucleotides remain problematical.