Considering that the DNA needs enzymes, to be formed, however enzymes need DNA to be formed too. What biomolecule was created first?

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    $\begingroup$ Welcome to Biology SE! What research did you do before asking this question? One theory is the "RNA world" hypothesis. There are numerous questions in this site discussing this issue. $\endgroup$ – vkehayas Nov 2 '17 at 15:16
  • $\begingroup$ Enzymes do not need DNA to form, they need RNA, important difference. RNA severs all the basic functions used in the production of RNA (template, amino acid tag, ribosomal), DNA is just a way of "storing" RNA. $\endgroup$ – John Nov 2 '17 at 16:13
  • $\begingroup$ As it stands this is a poorly phrased question. Are you asking about DNA and proteins, nucleic acids (to include RNA) and proteins, or the heredity material and enzymes (i.e. in an RNA world, the same molecule could have initially emerged as a self-replicating or catalytic molecule. Please clarify or — after reading RNA World questions — withdraw. $\endgroup$ – David Nov 3 '17 at 15:30
  • $\begingroup$ @David of course when i mean dna, i mean DNA and not all the nucleid acids. $\endgroup$ – user495758 Dec 8 '17 at 16:09
  • $\begingroup$ "Of course"? And you've read about the RNA world idea? Well then I'll answer your question when I'm feeling in the mood. But you're clearly in no hurry for answer. $\endgroup$ – David Dec 8 '17 at 22:51

If one is scientifically rigorous, the answer to this question is:

Nobody knows.

If one accepts the most commonly accepted (although not proven) view of the evolution of genomes and catalysis, the answer is:



The ‘RNA world’ hypothesis, mentioned by @vkehayas, postulates that the first genome was RNA, not DNA, and the first enzymes were also RNA. DNA genomes arose later (as did protein enzymes, although the timing of that event is irrelevant to the question as originally written).

Alternative Question

If one was not aware that RNA is thought to have preceded DNA as genome, and had not been aware of catalytic RNA, then one might have asked:

Which came first, RNA or protein?

And in fact, this question was originally asked by Francis Crick in the restricted context of the synthesis of proteins by ribosomes on mRNA and led him to remark.

“It is thus not impossible to imagine that the primitive machinery had no protein at all and consisted entirely of RNA.”

The later discovery of catalytic RNA provided a mechanistic basis for an original world in which RNA was a self-replicating genome.

(So the answer to the alternative question is that ‘RNA’ preceded protein.)

Supporting citations

I have kept this answer brief and only provide a single general reference because @vkehayas provides links to other questions about this topic on this list.


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