Now, once we form the fully processed mRNA molecule that no longer contains those intron sections, we now take and mix it with a special enzyme known as reverse transcriptase. Now, what reverse transcriptase does is it uses the mRNA molecule to form the DNA molecule. And so we take this mRNA, mix it with reverse transcriptase and we form a DNA molecule that is complementary to that mRNA molecule that has been fully processed and which no longer contains those introns. And because this DNA is complementary to the mRNA, this complementary DNA will no longer contain these orange sections, these intron sections, it will only contain the sequence of nucleotides that corresponds to these exons sections. So now we heat this double stranded molecule and we separate the mRNA and the DNA. Remember, this DNA is complementary to this mRNA.