cDNA (Complementary DNA) Animation

Complementary DNA (cDNA) is a double-stranded DNA version of an mRNA molecule, widely used in molecular biology and genetic research. Since introns are spliced out in eukaryotic mRNA, cDNA provides a more accurate representation of a functional gene than the genomic sequence alone.

Why Use cDNA Instead of mRNA ?

Researchers prefer cDNA over mRNA because :
✔ cDNA is more stable than mRNA, which is prone to degradation.
✔ Techniques for amplifying and purifying cDNA are well-established, unlike for individual RNA molecules.
✔ It directly represents the protein-coding sequence, making it highly valuable for gene expression studies and cloning applications.

cDNA Synthesis : Role of Reverse Transcriptase

cDNA is synthesized from mRNA templates using a special enzyme called reverse transcriptase, originally isolated from retroviruses. The process involves :
1️⃣ Reverse transcription : Reverse transcriptase converts mRNA into single-stranded DNA.
2️⃣ cDNA synthesis : The single-stranded DNA is then used as a template for double-stranded DNA synthesis.
3️⃣ Direct cloning : Unlike genomic DNA, cDNA does not require fragmentation or restriction enzyme digestion before cloning.