Inheritance and selection of the mitochondrial genome.

The functioning mitochondrial genome is essential for cellular energy production. Being strictly maternally inherited and possessing limited DNA repair capacity, mitochondrial DNA (mtDNA) replication errors tend to accumulate over time. If left unchecked, these errors can accumulate through the female germline over successive generations, potentially leading to species extinction. However, this outcome is not observed in most species, including humans, which implies the existence of mechanisms that counteract the progressive accumulation of deleterious mtDNA mutations. Recent technological advances are building a deeper understanding of the processes that preserve mtDNA integrity, including the molecular and cellular basis and timing of purifying selection. This new knowledge helps to explain how mtDNA can change rapidly over just a few generations, whilst remaining compatible with the independently inherited, evolving nuclear genome.