As far as we know, it is impossible to build a time machine that could physically transport us into the past, let us poke around and make observations, and then return to our own time to share whatever we've seen.

But it's entirely possible to know a lot about what the world was like before any human was

around to experience it. From KERA in Dallas, this is Think. I'm Chris Boyd. We can count tree

rings in petrified wood. We can dig up and examine fossils and take core

samples from the permafrost and make highly educated guesses. But we can actually do better than that.

As we learn to read the genetic codes of all living animals that exist right now, we can gain an

astonishing amount of information about the conditions in which their most ancient ancestors evolved,

and the reasons bodies contain genes that in the present moment don't seem to have any utility at all.

Some of this is already possible, even visible to the naked eye.

And my guest is hoping his new book will inspire the scientists of the future to tackle this kind of biological translation

with the better tools and deeper knowledge we hope they will have available to them.

Richard Dawkins is the inaugural Charles Simonyi Professor for the Public Understanding of Science

at Oxford University. His latest work is called The Genetic Book of the Dead, a Darwinian reverie.

Richard, welcome to think.

Thank you very much.

You remind us that Darwinism is really all about survival and reproduction, and specifically about gene survival.

Whatever sorts of bodies evolve to contain them, the ultimate winner of natural selection is not at the level

of species, right, but at the level of the individual gene.

That is correct.

Tell us more about that.

Yes. The thing about bodies is that they are mortal.

Genes are potentially immortal.

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