I loved the idea that biology was logical.

Ageing is very exciting. But if I didn't work on ageing, I'd want to work on the brain. There are really cool techniques you can use now. And bioinformatics. The methods you can use for comparing large data sets - that's so powerful.

In the early '90s, we discovered mutations that could double the normal life span of worms.

Maybe one day we will be able to take a pill that keeps us young and healthy much longer. I believe in my heart that this will happen.

Imagine that: If you could change one of the genes in an experiment, an aging gene, maybe you could slow down aging and extend lifespan.

Generally, older people in their fifties, sixties, and seventies are running most countries and are CEOs of corporations. Which isn't to say there aren't entrepreneurs, but if the young were better in every respect, there'd be no reason for the old. Our life span reflects our particular life strategy.

A big tree seemed even more beautiful to me when I imagined thousands of tiny photosynthesis machines inside every leaf. So I went to MIT and worked on bacteria because that's where people knew the most about these switches, how to control the genetics.