Inheritance and selection of the mitochondrial genome.

Mitochondrial DNA errors tend to accumulate over generations but are counteracted by mechanisms that preserve mtDNA integrity in most species, including humans.

• Why it matters: Understanding how mtDNA remains functional despite limited repair capacity is crucial because accumulation of deleterious mutations could lead to species extinction, yet most species avoid this outcome.
• What they did: Recent technological advances have enabled detailed study of the molecular and cellular processes, including purifying selection, that maintain mtDNA integrity across generations.
• The result: This knowledge explains how mtDNA can change rapidly over a few generations while remaining compatible with the evolving nuclear genome, highlighting mechanisms that prevent species extinction.