Why is DNA more stable than RNA? 4 Reasons

DNA is the genetic material in all organism; except some RNA viruses. What makes DNA more efficient than RNA for long term storage of genetic information?

Let’s understand the reasons.

Watch our video here: 4 Reasons Why DNA is more stable than RNA?

Reason 1:

Double-Stranded Structure: DNA is double-stranded, which provides more stability compared to the single-stranded structure of RNA.

How this Double-Stranded Structure provides stability to DNA?

• Hydrogen Bonding between bases: The two strands of DNA are held together by hydrogen bonds between complementary base pairs (Adenine pairs with Thymine by 2 hydrogen bonds and cytosine with guanine by 3 H-bonds). These H-bonds contribute to the stability of the DNA molecule.
• Base-Stacking Interactions: refers to the way in which bases are arranged one above the other in a DNA double helix.  Bases are stacked one above the other just like plates that also contribute to the stability of the DNA double helix.
• Charge Neutralization: The negatively-charged phosphate groups in the backbone of the DNA strands gets neutralized by the positive charge of histone proteins, conferring greater strength on the hydrogen bonds that connect the complementary strands. This enhances the stability of the DNA molecule.
• Complementary Base Pairing: Where two ringed purines always pairs with single ringed pyrimidines in perfect orientation. Each strand mirrors the other due to the anti-parallel orientation of the sugar-phosphate backbones and the complementary nature of the A-T and C-G base pairing.

Reason 2:

Deoxyribose Sugar: DNA contains deoxyribose sugar, which lacks a hydroxyl group at the 2’ carbon atom or lacks oxygen at the 2-C (actually it is 2-deoxy ribose). This absence of hydroxyl group makes DNA less susceptible to hydrolysis, contributing to its more stability compared to RNA.

Reason 3:

Nitrogenous base is Thymine instead of Uracil in RNA: DNA has thymine in the place of uracil in RNA. Thymine is more stable than uracil, contributing to the overall stability of DNA compared to RNA.

Reason 4:

Enzymatic Repair mechanisms: DNA is present in the nucleus where robust enzyme mediated DNA repair mechanisms are present to avoid any error or mismatch during replication or damage. RNA is primarily present in cytoplasm where there is no comparable repair mechanism, making it less stable than DNA.

All these factors make DNA a more stable molecule, best suited for long-term storage of genetic information in all organism. On the other hand, the relative instability of RNA is useful for its role in short-term tasks like mRNA, transmitting genetic information from DNA to protein.

Reference: Reference: Matange, K., Tuck, J. M., & Keung, A. J. (2021). DNA stability: a central design consideration for DNA data storage systems. Nature communications, 12(1), 1-9.