NCIt definition : DNA polymerases are not capable of de novo DNA synthesis and require synthesis of
a primer, usually by a DNA-dependent RNA polymerase (primase) to begin DNA synthesis.
In eukaryotic cells, the primer is synthesized by DNA polymerase alpha:primase. First,
the DNA primase portion of this complex synthesizes approximately 6-10 nucleotides
of RNA primer and then the DNA polymerase portion synthesizes an additional 20 nucleotides
of DNA. (from MedLine 11395402);