Mitochondrial DNA polymorphism: its role in longevity of the Irish population

The mtDNA genome has been implicated as playing a pivotal role in determini ng the longevity and success of the human lifespan. A PCR-RFLP methodology was used to identify polymorphic restriction enzyme sites within a 2643 bp region of the mtDNA genome and a table of genetic haplotypes for a healthy aged and a younger control cohort of patients was constructed. Forty-six di fferent mtDNA haplotypes and 11 groups of related haplotypes were identifie d across the two age groups but statistical analysis failed to show any sig nificant associations. The European J haplogroup, previously reported to be associated with longevity, was not found at an increased frequency within the Irish aged population (P = 0.36). However, the haplotypes comprising th e J haplogroup could be differentiated into two distinct branches by the pr esence or absence of the two polymorphic restriction sites, 16389g and 1600 0g. The branch of haplotypes defined by 16389g displayed a significant incr eased frequency in the aged samples (8%) compared to the controls (1%), P = 0.015. Inversely, the branch of haplotypes defined by 16000g displayed a s ignificant decreased frequency in the aged samples (4%) compared to the con trols (13%), P = 0.011. The polymorphism (mt5178A) associated with longevit y in the Japanese was not found in the Irish population, while the polymorp hism (mt9055A) associated with successful ageing in the French centenarians was found at an increased frequency in the Irish aged population (9%) comp ared to the younger control group (5%), but failed to reach a level of stat istical significance, P = 0.164, (C) 2001 Elsevier Science Inc. All rights reserved.