If you go far enough back, your genome connects you with bacteria, butterflies, and barracuda - the great chain of being linked together through DNA.

It turns out that every person alive today can trace his or her ancestry back to Africa. Everyone's DNA tells a story of a journey from an African homeland to wherever you live.

We spent an enormous amount of time as hominids and as primates living as hunter-gatherers. That is the natural way for us to live, and we're suddenly living in this profoundly unnatural way, and we're still in the process of adapting to it and working out how to live with it.

Imagine you're copying a very long document, and occasionally you'll put an A where there should be a C. And that mistake has been translated down through the generations, and more mistakes have accumulated. So the longer the lineage has been in existence, the more mistakes the sequence is going to have.

Science is an enterprise that should be cherished as an activity of the free human mind. Because it transforms who we are, how we live, and it gives us an understanding of our place in the universe.

I'm chairing a UNESCO committee on how to improve global Internet communications for science; help third-world people get onto the Net so they can be part of the process.

I was born in California, raised a vegetarian, and love science fiction, so don't tell me how I need to be in order to fit your standards.

The truth is that our race survived ignorance; it is our scientific genius that will do us in.