G. Lehmann, The Shraga Segal Department of Microbiology and Immunology, Center for Multidisciplinary Research on Aging, Ben-Gurion University of the Negev, Beer-Sheva, Israel.

Rapidly increasing data on completely sequenced mitochondrial DNA (mtDNA) in different species provide a possibility for comprehensive analysis of the relationships between mtDNA and longevity. We have recently shown that GC content of mtDNA and resting metabolic rate are two powerful predictors of mammalian longevity, which together explain more than three fourths of variation in maximum life span (MLS). To get further insight into the links between mtDNA and longevity, we analyzed coding and non-coding (D-loop region) sequences, the number of direct repeats, and the frequency of mtDNA encoded amino acids.

The remarkable finding of this study was that an increase in the mammalian MLS was associated with minimization of the mtDNA size via reduction of the D-loop region, primarily because of a decrease in the number of bases occupied by the direct repeats. The results obtained show for the first time the association between the D-loop region and species-specific longevity and suggest an important role for non-coding mtDNA and direct repeats in determination of the mammalian MLS. The data obtained were integrated with our previous results to provide a possible scenario for the links between MLS and mtDNA.