Two longevity pathways affect growth and metabolism in similar ways, and researchers have wondered for years whether the two routes coincide. A new study hints that these roads might not even lie on the same page of the atlas. Calorie restriction further extends the lives of mice already renowned for longevity due to a mutation in the Prop-1 gene. The results, reported in the 22 November issue of Nature, suggest that the two pathways don't overlap and indicate that researchers could travel a long way before they reach the maximum life-span of mice and perhaps humans.