What reagent is commonly used to decalcify bone during DNA extraction, and why?

What reagent is commonly used to decalcify bone during DNA extraction, and why?

• A. Hydrochloric acid; it dissolves calcium to release DNA.
• B. Edetate disodium (EDTA); it chelates calcium and frees DNA from the mineral matrix.
• C. Sodium hydroxide; it neutralizes minerals.
• D. Sodium chloride; it preserves DNA.

Answer: (B)

In bone DNA extraction, minerals like calcium in the hydroxyapatite matrix must be removed to access the DNA bound within the mineral lattice. A chelating agent is used to bind calcium ions and dissolve the mineral, freeing the DNA. Edetate disodium (EDTA) is the reagent of choice because it forms stable complexes with calcium, effectively demineralizing the bone while preserving DNA integrity. It also helps protect DNA by sequestering other divalent cations that are cofactors for nucleases, reducing degradation during extraction. Other options either aggressively degrade DNA or do not remove the mineral, making them less suitable for preserving DNA while enabling access to it.

In bone DNA extraction, minerals like calcium in the hydroxyapatite matrix must be removed to access the DNA bound within the mineral lattice. A chelating agent is used to bind calcium ions and dissolve the mineral, freeing the DNA. Edetate disodium (EDTA) is the reagent of choice because it forms stable complexes with calcium, effectively demineralizing the bone while preserving DNA integrity. It also helps protect DNA by sequestering other divalent cations that are cofactors for nucleases, reducing degradation during extraction. Other options either aggressively degrade DNA or do not remove the mineral, making them less suitable for preserving DNA while enabling access to it.