[Arctic and southern freshwater pearl mussel Margaritifera margaritifera with long and short life span as a model system for testing longevity mechanisms]

Abstract

The freshwater pearl mussel (Margaritifera margartifera) is one of the longest lived animals, attaining ages in excess of 150 years in polar climates. Because of its long life, the species may be useful for studying genetic and physiological mechanisms contributing to longevity. An ongoing study is comparing 6 southern populations in Spain, with maximum recorded ages of 28-40 years, to 3 Arctic populations in northwest Russia, with maximum ages of 114-190 years. Within Arctic populations, 40% of mussels live more than 100 years in rivers that are pristine. Possible evolutionary significance of northern longevity is an adaptation to severe cold and unstable environments in high gradient rivers. During winter, mussels have a near-famine existence during the Polar Night, and experience some shell damage from ice formation and flows. In summer, periodic droughts result in exposure and desiccation. In response to adversity, pearl mussels have acquired effective mechanisms for shell reparation and tissue healing and regeneration. Northern populations have low metabolic rates, reducing energy expenditure for growth under normal as well as extreme conditions. However, this species is capable of increasing metabolic rate for tissue regeneration and self-healing. The physiological adaptations to sustain longevity may provide useful clues to impedence of the aging process.