 How are genes replicated? The idea that genes are segments in a DNA double helix provides a straightforward answer to this question. Genes are faithfully replicated when the paired chains of a DNA molecule unwind and new chains are formed along side the separating strands by the pairing of complementary nucleotides. When the process is complete, two copies of the original double helix have been formed and hence the genes in the original DNA molecule have been effectively replicated.