The creation of c-dna (from an mrna transcript) begins when the DNA is transcribed first into mRNA which is then tarnslated into proteins. During this process all intron RNA is cut away from the RNA primary transcripts and the remaining parts of that are fused back together. This transcript splicing is called mRNA. From this point the code is then translated into an amino acid chain. Often it becomes necessary to create complimentary dna because the introns inhibit transcription. This new 'copy' is intron free. So, the first step is creating the cdna by using prokaryotic regulatory sequences. This is often called enzyme reverse transcriptase. This enzyme is what strips the introns away.
