I am not asking why RNA primer needs to be added, but rather why RNA nucleotides are added as a primer by Primase and replaced by DNA polymerase I? It seems very inefficient to first insert RNA nucleotides and then add DNA nucleotides when you could have evolved to just add DNA nucleotides directly, without having to add RNA nucleotides.

Perhaps, it is an evolutionary remnant? Proof that DNA arised RNA? What do you guys think?

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    $\begingroup$ Does this answer your question? What is the function of the RNA primer in DNA replication? $\endgroup$
    – David
    Jun 3 at 19:48
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    $\begingroup$ Welcome to SE Biology. At root, your question is a good one, but I have voted to close it as a duplicate for the following reason. You say you are not asking why an RNA primer is needed, but that is the self-same reason why the primer is RNA and needs to be replaced. In short only DNA-dependent RNA polymerases (of which primase is an example) can operate without a primer —DNA polymerases cannot. If they could there would be no need for a primer, the lagging strand could just be copied. WHY this difference is a matter for conjecture. The answers in the original question only make suggestions. $\endgroup$
    – David
    Jun 3 at 19:54


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