Abstract

The physiological mechanism underlying the well-established negative correlation between Gompertz postnatal growth constant and lifespan across mammalian species remains unclear. For the first time, this study shows that the energetic cost of biosynthesis plays a key role in this correlation. Previously, this cost has been thought to be a constant across species, and therefore was not considered a contributor to the variation in any life history traits. Here, we employ a newly proposed model to explain the physiological effect of the variation in this energetic cost on aging, and how it links growth and lifespan. The conventional life history theory suggested a tradeoff between growth and health of animals, but the new findings here suggest that allocating more energy to biosynthesis may reduce the energetic requirement of somatic maintenance and extend lifespan, and therefore they reveal a more complex nature of the tradeoff.