S4.13 Six toed cats and cyclops lambs: The story of Sonic Hedgehog
Hello, and welcome to Genetics Unzipped - the Genetics Society podcast, with me, Dr Kat Arney. In this episode, supported by the Institute of Genetics and Cancer at the University of Edinburgh, I sit down with Professor Bob Hill to take a look at the story of our favourite gene - we’ve all got one, right? From six-toed cats to cyclops lambs (and, of course, it’s fabulous name) the Sonic Hedgehog gene has a fascinating history, as well as a whole bunch of interesting science behind it.
It all started with a photo of a cat. I was hiding at the back of a scientific conference at the Royal Society in London when a cuddly looking cat with unusually big feet caught my eye. ‘This is a Hemingway cat,’ said the lecturer, pointing at the animal on the large screen behind him. ‘They have six toes – they’re polydactyl. Ernest Hemingway was said to be fond of them, and they still live on his estate in Florida today. And here … ’ he poked at the computer, changing the slide to one covered with photos of misshapen human hands, ‘ … are polydactyl children with extra digits. It’s the same genetic mistake that causes them. ’
Looking at a six-toed cat or six-fingered human, a natural assumption might be that it’s due to a fault in a gene. But it’s not. In fact the cause lies in a faulty region of DNA that acts as a control switch, normally turning a gene on at the right time in the right place to direct the formation of fingers and toes as a baby or kitten grows in the womb. Not only that, but the switch is miles away (in molecular terms) from the gene it acts upon. Learning about the Hemingway cats and their broken switches got me thinking about my own understanding of how genes work, and how I explain it to the public through my work as a science writer and broadcaster.
If you’ve ever heard me give a talk about the wonders of genetics, you might well have heard that passage before. It’s the very start of my first book, Herding Hemingway’s Cats, describing the event that set me off on a scientific odyssey to find out how our genes work. It turns out it’s really complicated, so you’ll have to read the book to find out what I discovered.
Throughout the whole process I never lost sight of the amazing phenomenon that this researcher was describing, of how a single DNA letter ‘change’ in a control switch for a gene could have such an impact, whether in a human hand or a cat’s paw. The gene itself is none other than Sonic Hedgehog - not only a strong contender for the ‘best named gene’ award, but a remarkable molecular entity whose influence goes deep within our bodies and stretches out across the animal kingdom.
And the researcher whose presentation so entranced me at the Royal Society? Click Here to find out who it could be!
If you’re curious to know more about Sonic Hedgehog, and how our genes work in general then do check out my first book, Herding Hemingway’s Cats, which is available in paperback, ebook and audiobook from all good bookstores (and the evil ones too).
And you can also check out the short programme I made about this so-called Cyclops gene for my BBC Radio 4 series Ingenious - you can find the link in the page for this podcast at GeneticsUnzipped.com
That’s all for now. Thanks to Bob Hill from the MRC Human Genetics Unit at the Institute of Genetics and Cancer at the University of Edinburgh for chatting with me for a very long time about Sonic Hedgehog, to the Institute of Genetics and Cancer for supporting this episode, and to Dee Davison for setting it all up.
We’ll be back next time finding out about how to harness the power of genetics for everyone, from tribal communities to inner cities to whole continents.
For more information about this podcast including show notes, transcripts, links, references, music credits and everything else head over to geneticsunzipped.com You can find us on Twitter @geneticsunzip and please do take a moment to rate and review us on Apple podcasts - it really makes a difference and helps more people discover the show.
Genetics Unzipped is written and presented by me, Kat Arney. It is produced by First Create the Media for The Genetics Society - one of the oldest learned societies in the world dedicated to supporting and promoting the research, teaching and application of genetics. You can find out more and apply to join at genetics.org.uk. Our theme music was composed by Dan Pollard, and the logo was designed by James Mayall, and audio production was by Hannah Varrall. Thanks for listening, and until next time, goodbye.
