Using your nondominant hand, write your name, address, and phone number while circling your opposite foot counterclockwise. - David A. Sinclair

When the Sir2 enzyme is sitting on the mating-type genes, they remain silent and the cell continues to mate and reproduce. But when a DNA break occurs, Sir2 is recruited to the break to remove the acetyl tags from the histones at the DNA break. This bundles up the histones to prevent the frayed DNA from being chewed back and to help recruit other repair proteins. Once the DNA repair is complete, most of the Sir2 protein goes back to the mating-type genes to silence them and restore fertility. That is, unless there is another emergency, such as the massive genome instability that occurs when ERCs accumulate in the nucleoli of old yeast cells.

Up until the second half of the twentieth century, it was generally accepted that organisms grow old and die “for the good of the species” — an idea that dates back to Aristotle, if not further.

We also knew that many other health-promoting molecules, and chemical derivatives of them, are produced in abundance by stressed plants; we get resveratrol from grapes, aspirin from willow bark, metformin from lilacs, epigallocatechin gallate from green tea, quercetin from fruits, and allicin from garlic. This, we believe, is evidence of xenohormesis — the idea that stressed plants produce chemicals for themselves that tell their cells to hunker down and survive.