What is mitochondrial DNA (mtDNA)?

What is mitochondrial DNA (mtDNA)?

• A. DNA found inside the nucleus and inherited from both parents.
• B. RNA in mitochondria.
• C. A type of protein-coding gene in the nucleus.
• D. DNA found outside the nucleus of the cell, inherited only from the mother, and useful for characterizing degraded DNA.

Answer: (D)

Mitochondrial DNA is the small circular genome housed in mitochondria, the energy-producing parts of the cell, which are located outside the cell nucleus. It is inherited only from the mother, because the mitochondria in sperm are typically not transmitted to the offspring. There are many copies of mtDNA per cell, thousands in some cells, which makes it especially useful when DNA is degraded or present in very small amounts. This abundance helps forensic scientists analyze samples where nuclear DNA is limited or damaged. This differs from nuclear DNA, which lives in the cell nucleus and is inherited from both parents. MtDNA is DNA (not RNA) and is not a nuclear protein-coding gene, but a separate, maternally inherited genome inside the mitochondria.

Mitochondrial DNA is the small circular genome housed in mitochondria, the energy-producing parts of the cell, which are located outside the cell nucleus. It is inherited only from the mother, because the mitochondria in sperm are typically not transmitted to the offspring. There are many copies of mtDNA per cell, thousands in some cells, which makes it especially useful when DNA is degraded or present in very small amounts. This abundance helps forensic scientists analyze samples where nuclear DNA is limited or damaged.

This differs from nuclear DNA, which lives in the cell nucleus and is inherited from both parents. MtDNA is DNA (not RNA) and is not a nuclear protein-coding gene, but a separate, maternally inherited genome inside the mitochondria.