S4.09 Genes and giants - the science of big and small

Hello, and welcome to Genetics Unzipped - the Genetics Society podcast, with me, Dr Kat Arney. In this episode we’re taking a look at the genetics of giants and the science of small. Why do some species grow so large? What’s the genetic legacy behind the Giants of Ireland? And what was it about life on a Mediterranean island that miniaturised a mammoth?

Go big or go home

When it comes to understanding the genetics of nature’s giants, we don’t actually know all that much, but the genome of the world’s largest living rodent – the capybara – does give us some pointers. It’s no blue whale or African elephant, but this famously chilled-out semi-aquatic mammal is a veritable behemoth compared to its ratty relatives. With an average body mass of 55 kilos, the capybara is around 2000 times bigger than a mouse and 60 times larger than its closest living relative, the guinea-pig-like rocky cavy.  Click here to learn more about how the majestic capybara and nature’s other giants have managed being big.

Giant steps - Charles Byrne, the Irish Giant

The Irish giant’s dying wish was to be buried in a lead coffin. At sea. Off Margate.

Born in Londonderry, Northern Ireland in 1761, Charles Byrne is said to have grown “like a corn stalk”, quickly reaching a staggering 7 foot 7 inches. In 1782, at the age of 21, he travelled to London, where he sought – and to some extent found – his fame and a small fortune. Click here to find out if Charles Byrne got his dying wish.

Island life

Like in the TV series Lost, when you live on an island, things can get more than a little weird. We’re not talking about spooky supernatural stuff here, but the unexpected appearance of giants and dwarves. Click here to discover the fascinating effect of island life on evolution.

That’s all for now. Thanks very much to Henry Nicholls for researching and writing this episode. You can find him on Twitter at @wayofthepanda and he’s the author of several wonderful books about nature, including Lonesome George, about the Galapagos tortoise who’s the last survivor of his species; Galapagos, about George’s island home; and The Way of the Panda, obviously enough about giant pandas. His latest book, Sleepyhead, is an exploration of sleep disorders, based on his own experience of narcolepsy. 

Next time we’re taking to the night skies, with a look at the genetics of bats.

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 with additional research and scripting by Henry Nicholls. 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.

• Sound effects licensed from Epidemic Sound

• Image credits:

  • African Elephant with calf: zambezi via Envato

  • Capybara: lightpoet via Envato

  • Charles Byrne Print: By Thomas Rowland. Published by T Smith © The Trustees of the British Museum, released as CC BY-NC-SA 4.0

  • Island Life: twenty20photos via Envato