The language of genes has become common parlance. We know they make your eyes
blue, your hair curly or your nose straight. The media tells us that our genes control the
risk of cancer, heart disease, alcoholism or Alzheimer’s. The cost of DNA sequencing
has plummeted from billions of pounds to a few hundred, and gene-based advances in
medicine hold huge promise.
So we’ve all heard of genes, but how do they actually work?
According to legend, Ernest Hemingway was once given a six-toed cat by an old sea
captain, and her distinctive descendants still roam the writer’s Florida estate today.
Scientists now know that the fault driving this profusion of digits lies in a tiny genetic
control switch, miles away (in molecular terms) from the gene that ‘makes’ toes. And it's
the same mistake that gives rise to multi-toed humans too.
There are 2.2 metres of DNA inside every one of your cells, encoding roughly 20,000
genes. These are the 'recipes' that tell our cells how to make the building blocks of life,
along with myriad control switches ensuring they're turned on and off at the right time
and in the right place. But rather than a static string of genetic code, this is a dynamic,
writhing biological library. And figuring out how it all works – how your genes make you,
you – is a major challenge for researchers around the world.
Drawing on stories ranging from six-toed cats and stickleback hips to wobbly worms
and zombie genes, geneticist Kat Arney explores the how our genes work, creating a
companion reader to the book of life itself.

About the Author

Following a doctorate in developmental genetics at Cambridge University and a brief research career, Kat Arney is now Science Communications Manager at Cancer Research UK where she translates science-speak into plain English for the charity's supporters, the media and the general public. Kat is also a freelance science writer and broadcaster, whose work has appeared in the Guardian, New Scientist, BBC Online, Al- Jazeera Online and Mosaic. According to BBC America, Kat is one of the 'Top 10 Brits Who Make Science Sexy', and she regularly appears on national TV and radio shows talking about the latest cancer research. She has co-presented the award-winning Naked Scientists podcast and radio show for more than a decade, presents and produces the Naked Genetics monthly podcast, has fronted several BBC Radio 4 science documentaries, and doesn't sleep very much.