The Curious Cases of Rutherford and Fry

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The Curious Cases of Rutherford & Fry

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Factual: Science & Nature

Factual: Science & Nature: Science & Technology

Science sleuths Dr Adam Rutherford and Dr Hannah Fry investigate everyday mysteries.

Science sleuths Dr Adam Rutherford and Dr Hannah Fry investigate everyday mysteries sent by listeners.

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The Curious Cases of Rutherford & Fry: Series 16: The Zedonk Problem

The Zedonk Problem

Series 16

BBC Radio 4 - The Curious Cases of Rutherford & Fry, Series 16, The Zedonk Problem

What are ligons and tigers? What is a species?

What determines whether species can interbreed?  Scientists Aoife LcLysaght, Kit Yates and Joana Meier explain.  From 2020.

‘Today I learnt that tigons and ligers are what you get when lions and tigers interbreed?!’ surprised listener Jamz G tells the doctors. ‘What determines whether species can interbreed?’ 

Geneticist Aoife McLysaght studies molecular evolution. She explains the modern definition of a species, built on ideas from Aristotle, Linnaeus and Darwin: a species is a group of organisms capable of interbreeding to produce fertile offspring. Hybrids – such as ligons and tigers – are usually infertile, because their common ancestors long ago diverged into the lions and tigers we know today. However, this definition isn’t absolute, and there are many ways a new species can be formed.

Hybrids also offer rich study subjects for scientists. Mathematical biologist Kit Yates discusses why he’s been reading research papers about hebras and zorses (horse x zebra) as their patterns offer insights into how cells spread and develop into organisms, building on a prediction made by codebreaking mathematician Alan Turing.

And it turns out that these hybrids are even more intriguing. As speciation and evolution expert Joana Meier explains, hybrids are not always infertile. Hybridisation can lead to successful new species arising, such as in Lake Victoria’s cichlid fish, who it seems have been having a wild evolutionary party for the last 15,000 years. And the picture gets even murkier when we discover that modern genetics reveals our human ancestors successfully mated with Neanderthals. 

Presenters: Hannah Fry & Adam Rutherford

Producer: Jen Whyntie

First broadcast on BBC Radio 4 in July 2020.

The Curious Cases of Rutherford & Fry: Series 16

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Intelligent speech, the most insightful journalism, the wittiest comedy, the most fascinating features and the most compelling drama and readings anywhere in UK radio.

Dr Adam Rutherford and Dr Hannah Fry investigate everyday mysteries sent by listeners.

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The Zedonk Problem

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