You're about to listen to a BBC podcast and trust me you'll get there in a moment but if you're a comedy fan

I'd really like to tell you a bit about what we do. I'm Julie Mackenzie and I commission comedy

podcast at the BBC. It's a bit of a dream job really.

Comedy is a fantastic joyous thing to do because really you're making people laugh,

making people's days a bit better, helping them process, all manner of things.

But you know I also know that comedy is really

subjective and everyone has different tastes so we've got a huge range of comedy on offer

from satire to silly shocking to soothing profound to just general pratting about. So if you

fancy a laugh, find your next comedy at BBC Sounds.

BBC Sounds, Music, radio podcasts.

Thanks for downloading this episode of In Our Time.

There's a reading list to go with it on our website,

and you can get news about our programs if you follow us on Twitter at BBC in our time. I hope you

enjoy the programs. Hello, as a rule of thumb one species cannot mate with another

species and that very fact is a way of telling species apart. But there are hybrids,

which were once thought the exception to this rule, the offspring of different species.

Yet the more we look, the more common these hybrids appear to be, and the more vital to evolution

from the beginning of life to now and from now onwards.

And they challenge your idea what a species is and what separates one species from another.

With me to discuss hybrids are Sandra Knapp, Tropical Botanist at the Natural History Museum,

Nicola Nadeau, lecturer in Evolutionary Biology at the University of Sheffield, and Steve Jones, Senior Research Fellow in Genetics at University College London.

Steve Jones, can you tell us what a hybrid is?

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