The population in the developed world has experienced a significant increase in life expectancy over the last 50 years. Simultaneously, while the onset of comorbidities has been deferred to older age groups, health-care expenditure has grown dramatically, primarily owing to the advancement of medical technology and the expansion of individual income levels, along with population ageing in the w...

Human ageing has been predicted to be caused by the accumulation of molecular damage in cells and tissues. Somatic mitochondrial DNA (mtDNA) mutations have been documented in a number of ageing tissues and have been shown to be associated with cellular mitochondrial dysfunction. It is unknown whether there are selective constraints, which have been shown to occur in the germline, on the occurre...